jp@adams:~$

	jp@adams:/tmp$

	bash-2.03$ pwd

	/tmp



	bash-2.03$ export PS1='[\u@\h \w]$ '

	[jp@solaris8 /tmp]$

	bash-2.03$ pwd

	/tmp/dir2



	bash-2.03$ pwd -L

	/tmp/dir2



	bash-2.03$ pwd -P

	/tmp/dir1

	$ type which

	which is hashed (/usr/bin/which)



	$ type ls

	ls is aliased to `ls -F -h'



	$ type -a ls

	ls is aliased to `ls -F -h'

	ls is /bin/ls



	$ which which

	/usr/bin/which

	$ apropos music

	cms (4) - Creative Music System device driver



	$ man -k music

	cms (4) - Creative Music System device driver

	$ touch /tmp/sample_file



	$ ls /tmp/sample_file

	/tmp/sample_file



	$ ls -l /tmp/sample_file

	-rw-r--r-- 1 jp	         jp            0 Dec 18 15:03 /tmp/sample_file



	$ stat /tmp/sample_file

	File: "/tmp/sample_file"

	Size: 0           Blocks: 0        IO Block: 4096   Regular File

	Device: 303h/771d Inode:  2310201    Links: 1

	Access: (0644/-rw-r--r--) Uid: (  501/      jp)   Gid: ( 501/        jp)

	Access: Sun Dec 18 15:03:35 2005

	Modify: Sun Dec 18 15:03:35 2005

	Change: Sun Dec 18 15:03:42 2005



	$ file /tmp/sample_file

	/tmp/sample_file: empty



	$ file -b /tmp/sample_file

	empty



	$ echo '#!/bin/bash -' > /tmp/sample_file



	$ file /tmp/sample_file

	/tmp/sample_file: Bourne-Again shell script text executable



	$ file -b /tmp/sample_file

	Bourne-Again shell script text executable

	$ ls -l /tmp/sample_file

	-rw-r--r--	  1 jp         jp                14 Dec 18 15:04 /tmp/sample_file



	$ stat -c'%A %h %U %G %s %y %n' /tmp/sample_file

	-rw-r--r-- 1 jp jp 14 Sun Dec 18 15:04:12 2005 /tmp/sample_file



	$ find /tmp/ -name sample_file -printf '%m %n %u %g %t %p'

	644 1 jp jp Sun Dec 18 15:04:12 2005 /tmp/sample_file

	ls -d .*

	ls -d .b*

	ls -d .[!.]*

	$ grep -l 'PATH' ~/.[!.]*

	/home/jp/.bash_history

	/home/jp/.bash_profile

	$ echo A coffee is $5?!

	A coffee is ?!



	$ echo "A coffee is $5?!"

	-bash: !": event not found



	$ echo 'A coffee is $5?!'

	A coffee is $5?!

	$ echo 'A coffee is $5 for' "$USER" '?!'

	A coffee is $5 for jp ?!



	$ echo "A coffee is \$5 for $USER?\!"

	A coffee is $5 for jp?\!



	$ echo "A coffee is \$5 for $USER?! "

	A coffee is $5 for jp?!

	# We'll get a continuation prompt since we now have unbalanced quotes

	$ echo '$USER won't pay $5 for coffee.'

	> ^C



	# WRONG

	$ echo "$USER won't pay $5 for coffee."

	jp won't pay for coffee.



	# Works

	$ echo "$USER won't pay \$5 for coffee."

	jp won't pay $5 for coffee.



	# Also works

	$ echo 'I won'\''t pay $5 for coffee.'

	I won't pay $5 for coffee.

	# type cd

	cd is a shell builtin



	# type awk

	awk is /bin/awk



	# which cd

	/usr/bin/which: no cd in (/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/

	sbin:/usr/bin/X11:/usr/X11R6/bin:/root/bin)



	# which awk

	/bin/awk

	# help help

	help: help [-s] [pattern ...]

	    Display helpful information about builtin commands. If PATTERN is

	    specified, gives detailed help on all commands matching PATTERN,

	    otherwise a list of the builtins is printed. The -s option

	    restricts the output for each builtin command matching PATTERN to

	    a short usage synopsis.

	#!/usr/bin/env bash

	# cookbook filename: interactive



	case "$-" in

	    *i*) # Code for interactive shell here

	         ;;

	    *)   # Code for non-interactive shell here

	         ;;

	esac

	if [ "$PS1" ]; then

	    echo This shell is interactive

	else

	    echo This shell is not interactive

	fi

	$ bash --version

	GNU bash, version 3.00.16(1)-release (i386-pc-solaris2.10)

	Copyright (C) 2004 Free Software Foundation, Inc.

	cam:pK1Z9BCJbzCrBNrkjRUdUiTtFOh/:501:100:Cameron Newham:/home/cam:/bin/bash

	cc:kfDKDjfkeDJKJySFgJFWErrElpe/:502:100:Cheshire Cat:/home/cc:/bin/bash

	pkg_add -vr bash

	pkg_add -vu ftp://ftp.netbsd.org/pub/NetBSD/packages/pkgsrc-2005Q3/NetBSD-2.0/i386/

	All/bash-3.0pl16nb3.tgz

	pkg_add -vr ftp://ftp.openbsd.org/pub/OpenBSD/3.8/packages/i386/bash-3.0.16p1.tgz

Solaris 2.x, Solaris 7, and Solaris 8 users can get a precompiled version of bash-3.0 from the Sunfreeware site. Sun ships bash-2.03 with Solaris 8 distributions, ships bash-2.05 as a supported part of Solaris 9, and ships bash-3.0 as a supported part of Solaris 10 (directly on the Solaris 10 CD).

AIX users can get precompiled versions of older releases of bash for various versions of AIX from Groupe Bull, and sources and binaries of current releases for various AIX releases from UCLA. IBM makes bash-3.0 available for AIX 5L as part of the AIX tool-box for [GNU/]Linux applications. They use RPM format; you can get RPM for AIX from there, too.

SGI users can get an installable version of bash-2.05b from the SGI Freeware page.

HP-UX users can get bash-3.0 binaries and source code from the Software Porting and Archive Center for HP-UX.

Tru64 Unix users can get sources and binaries for bash-2.05b from the HP/Compaq Tru64 Unix Open Source Software Collection.

What Is Cygwin

Cygwin is a Linux-like environment for Windows. It consists of two parts:

• A DLL (cygwin1.dll), which acts as a Linux API emulation layer providing substantial Linux API functionality.
• A collection of tools, which provide Linux look and feel.
  The Cygwin DLL works with all non-beta, non "release candidate," x86 32-bit versions of Windows since Windows 95, with the exception of Windows CE.
  What Isn't Cygwin
• Cygwin is not a way to run native Linux apps on Windows. You have to rebuild your application from source if you want to get it running on Windows.
• Cygwin is not a way to magically make native Windows apps aware of Unix functionality (e.g., signals, ptys). Again, you need to build your apps from source if you want to take advantage of Cygwin functionality.

polarhome.com is non commercial, educational effort for popularization of shell enabled operating systems and Internet services, offering shell accounts, mail and other online services on all available systems (currently on Linux, OpenVMS, Solaris, AIX, QNX, IRIX, HP-UX, Tru64, FreeBSD, OpenBSD, NetBSD and OPENSTEP).

[…]

Note: this site is continuously under construction and running on slow lines and low capacity servers that have been retired, therefore as a non commercial site user/visitor, nobody should have too high expectations in any meaning of the word. Even if polarhome.com does all to provide services on professional level, users should not expect more than "AS-IS".

polarhome.com is a distributed site, but more than 90% of polarhome realm is located in Stockholm, Sweden.

	echo Please wait.

	Please wait.

	$ echo Please wait.

	Please wait.

	$

	$ echo this    was     very    widely    spaced

	this was very widely spaced

	$

	$ echo "this was   very   widely    spaced"

	this    was  very  widely    spaced

	$

	$ echo 'this  was  very   widely   spaced'

	this    was   very  widely  spaced

	$

	$ printf '%s = %d\n' Lines $LINES

	Lines = 24

	$

	$ printf '%-10.10s = %4.2f\n' 'GigaHerz' 1.92735

	GigaHerz   = 1.93

	$

	$ printf '%10.10s = %4.2f\n' 'GigaHerz' 1.92735

	GigaHerz =   1.93

	$

	

	$ printf "%s %s" next prompt

	next prompt$

	$ echo -n prompt

	prompt$

	$ echo -e 'hi\c'

	hi$

	$ echo fill it up

	fill it up

	$ echo fill it up > file.txt	

	$

	$ cat file.txt

	fill it up

	$

	$ cat first.half second.half > whole.file

	$ echo some more data > /tmp/echo.out

	$ echo some more data > ../../over.here

	$ ls

	a.out cong.txt def.conf  file.txt  more.txt  zebra.list

	$

	$ ls > /tmp/save.out

	$ cat /tmp/save.out

	a.out

	cong.txt

	def.conf

	file.txt

	more.txt.

	zebra.list

	$

	$ ls -C > /tmp/save.out

	$ cat /tmp/save.out

	a.out cong.txt def.conf file.txt more.txt zebra.list

	$

	$ ls -1

	a.out

	Cong.txt

	def.conf.

	file.txt

	more.txt

	save.out

	zebra.list

	$

	$ myprogram 1> messages.out 2> message.err

	$ myprogram > messages.out 2> message.err

	$ both >& outfile

	$ both &> outfile

	$ both > outfile 2>&1

	$ both 2> outfile 1>&2

	$ ls > /tmp/ls.out

	$ cd ../elsewhere

	$ ls >> /tmp/ls.out

	$ cd ../anotherdir

	$ ls >> /tmp.ls.out

	$

	$ tail +2 lines

	Line 2



	Line 4

	Line 5

	$ find / -name myfile -print 2> /dev/null

	$ noisy >/dev/null 2>&1

	$ pwd; ls; cd ../elsewhere; pwd; ls > /tmp/all.out

	$ { pwd; ls; cd ../elsewhere; pwd; ls; } > /tmp/all.out

	$ (pwd; ls; cd ../elsewhere; pwd; ls) > /tmp/all.out

	$ cat one.file another.file > /tmp/cat.out

	$ sort < /tmp/cat.out

	...

	$ rm /tmp/cat.out

	$ cat one.file another.file | sort

	$ cat my* | tr 'a-z' 'A-Z' | uniq | awk -f transform.awk | wc

	$ sort /tmp/cat.out

	$ sort < /tmp/cat.out

	$ cat my* | tr 'a-z' 'A-Z' | uniq | awk -f transform.awk | wc

	$ ... uniq | tee /tmp/x.x | awk -f transform.awk ...

	find / -name '*.c' -print | less

	find / -name '*.c' -print > /tmp/all.my.sources

	find / -name '*.c' -print | tee /tmp/all.my.sources

	$ rm my.java your.c their.*

	find . -name '*.c' | rm

	$ rm $(find . -name '*.class')

	$

	$ find . -name '*.class'

	First.class

	Other.class

	$ rm $(find . -name '*.class')

	$

	$ divert 3> file.three 4> file.four 5> file.five 6> else.where

	$

	$ gcc bad.c

	bad.c: In function `main':

	bad.c:3: error: `bad' undeclared (first use in this function)

	bad.c:3: error: (Each undeclared identifier is reported only once

	bad.c:3: error: for each function it appears in.)

	bad.c:3: error: parse error before "c"

	$

	$ gcc bad.c > save.it

	bad.c: In function `main':

	bad.c:3: error: `bad' undeclared (first use in this function)

	bad.c:3: error: (Each undeclared identifier is reported only once

	bad.c:3: error: for each function it appears in.)

	bad.c:3: error: parse error before "c"

	$

	$ ls -l save.it

	-rw-r--r-- 1 albing users 0 2005-11-13 15:30 save.it

	$ cat save.it

	$

	$ gcc bad.c 2> save.it

	$

	$ ./myscript 3>&1 1>stdout.logfile 2>&3- | tee -a stderr.logfile

$ ./myscript 3>&1 1>&2 2>&3

	$ ./myscript 3>&1 1>stdout.logfile 2>&3- | tee -a stderr.logfile

	$ set -o noclobber

	$

	$ set +o noclobber

	$

	$ set +o noclobber

	$ echo something > my.file

	$ echo some more > my.file

	$ set -o noclobber

	$ echo something > my.file

	bash: my.file: cannot overwrite existing file

	$ echo some more >> my.file

	$	

	$ echo useless data > some.file

	$ echo important data > other.file

	$ set -o noclobber

	$ cp some.file other.file

	$

	$ echo something > my.file

	$ set -o noclobber

	$ echo some more >| my.file

	$ cat my.file

	some more

	$ echo once again > my.file

	bash: my.file: cannot overwrite existing file

	$

	 $ wc < my.file

	$ cat ext

	#

	# 

	here is a "here" document

	#

	grep $1 <<EOF

	mike x.123

	joe  x.234

	sue  x.555

	pete x.818

	sara x.822

	bill x.919

	EOF

	$

	$ ext bill

	bill x.919

	$

	$ ext 555

	sue x.555

	$

	$ grep somestring file.txt

	$ grep myvar *.c

	grep $1 phonenumbers.txt

	$ cat donors

	#

	# simple lookup of our generous donors

	#

	grep $1 <<EOF

	# name amt

	pete $100

	joe  $200

	sam  $ 25

	bill $ 9

	EOF

	$

	$ ./donors bill

	pete bill00

	bill $  9

	$ ./donors pete

	pete pete00

	$

	# solution

	grep $1 <<EOF

	pete $100

	joe  $200

	sam  $ 25

	bill $ 9

	EOF

	$ ./donors pete

	pete $100

	$

	$ cat myscript.sh

	...

	     grep $1 <<-'EOF'

	        lots of data

	        can go here

	        it's indented with tabs

	        to match the script's indenting

	        but the leading tabs are

	        discarded when read

	        EOF

	    ls

	...

	$

	read

	read - p "answer me this " ANSWER

	read PRE MID POST

	# cookbook filename: func_choose



	# Let the user make a choice about something and execute code based on

	# the answer

	# Called like: choose <default (y or n)> <prompt> <yes action> <no action>

	# e.g. choose "y" \

	#       "Do you want to play a game?" \

	#       /usr/games/GlobalThermonucularWar \

	#       'printf "%b" "See you later Professor Falkin."' >&2

	# Returns: nothing

	function choose {

	

	    local default="$1"

	    local prompt="$2"

	    local choice_yes="$3"

	    local choice_no="$4" 

	    local answer

	

	    read -p "$prompt" answer

	    [ -z "$answer" ] && answer="$default"



	    case "$answer" in

	        [yY1] ) exec "$choice_yes"

	            # error check

	            ;;

	        [nN0] ) exec "$choice_no"



	            # error check

	            ;;

	        *     ) printf "%b" "Unexpected answer '$answer'!" >&2 ;;

	    esac

	} # end of function choose

	# cookbook filename: func_choice.1



	# Let the user make a choice about something and return a standardized

	# answer. How the default is handled and what happens next is up to	

	# the if/then after the choice in main

	# Called like: choice <promtp>

	# e.g. choice "Do you want to play a game?"

	$ Returns: global variable CHOICE

	function choice {



	   CHOICE='' 

	   local prompt="$*"

	   local answer



	   read -p "$prompt" answer

	   case "$answer" in

	        [yY1] ) CHOICE='y';;

	        [nN0] ) CHOICE='n';;

	        *     ) CHOICE="$answer";;

	   esac

	} # end of function choice

	# cookbook filename: select_dir



	directorylist="Finished $(ls /)"



	PS3='Directory to process? ' # Set a useful select prompt

	until [ "$directory" == "Finished" ]; do



	    printf "%b" "\a\n\nSelect a directory to process:\n" >&2

	    select directory in $directorylist; do



	        # User types a number which is stored in $REPLY, but select

	        # returns the value of the entry

	        if [ "$directory" = "Finished" ]; then

	            echo "Finished processing directories."

	            break

	        elif [ -n "$directory" ]; then

	            echo "You chose number $REPLY, processing $directory..."

	            # Do something here

	            break	

	        else

	            echo "Invalid selection!"

	        fi # end of handle user's selection

	 

	    done # end of select a directory

	done # end of while not finished

	read -s -p "password: " PASSWD

	printf "%b" "\n"

	read -s -p "password: " PASSWD ; printf "%b" "\n"

	$ someprog

	$ echo $PATH

	/bin:/usr/bin:/usr/local/bin:.

	$

	$ somecommand

	it works...

	$ echo $?

	0

	$ badcommand

	it fails...

	$ echo $?

	1

	$

	$ badcommand

	it fails...

	$ echo $?

	1

	$ echo $?

	0

	$

	$ badcommand

	it fails...

	$ STAT=$?

	$ echo $STAT

	1

	$ echo $STAT

	1

	$

	$ cat > simple.script

	long

	medium

	short

	^D                      # Ctrl-D, not visible

	$ bash ./simple.script

	$ long ; medium ; short

	$ long && medium && short

	$ long &

	[1] 4592

	$ medium &

	[2] 4593

	$ short

	$

	$ long & medium & short

	[1] 4592

	2] 4593

	$

	cd mytmp

	if (( $? )); then rm * ; fi

	$ cd mytmp && rm *

	cd mytmp

	if (( $? )); then rm * ; fi

	set -e

	cd mytmp

	rm *

	$ nohup long &

	nohup: appending output to `nohup.out'

	$

	cmd || printf "%b" "cmd failed. You're on your own\n"

	cmd || printf "%b" "FAILED.\n" ; exit 1

	cmd || { printf "%b" "FAILED.\n" ; exit 1 ; }

	FN=/tmp/x.x

	PROG=echo

	$PROG $FN

	PROG=cat

	$PROG $FN

	for SCRIPT in /path/to/scripts/dir/*

	do

		if [ -f $SCRIPT -a -x $SCRIPT ]

		then

			$SCRIPT

		fi

	done

	#

	# This is a comment.

	#

	# Use comments frequently.

	# Comments are your friends.

	# replace the semi with a blank

	NEWPATH=${PATH/;/ }

	#

	# switch the text on either side of a semi

	sed -e 's/^\(.*\);\(.*\)$/\2;\1/' < $FILE

	#!/usr/bin/env bash

	# cookbook filename: embedded_documentation



	echo 'Shell script code goes here'

	

	# Use a : NOOP and here document to embed documentation,

	: <<'END_OF_DOCS'



	Embedded documentation such as Perl's Plain Old Documentation (POD),

	or even plain text here.



	Any accurate documentation is better than none at all.

	

	Sample documentation in Perl's Plain Old Documentation (POD) format adapted from

	CODE/ch07/Ch07.001_Best_Ex7.1 and 7.2 in Perl Best Practices.



	=head1 NAME



	MY~PROGRAM--One line description here



	=head1 SYNOPSIS



	  MY~PROGRAM [OPTIONS] <file>

	

	=head1 OPTIONS



	  -h = This usage.

	  -v = Be verbose.

	  -V = Show version, copyright and license information.





	=head1 DESCRIPTION



	A full description of the application and its features.

	May include numerous subsections (i.e. =head2, =head3, etc.)





	[...]



	=head1 LICENSE AND COPYRIGHT



	=cut



	END_OF_DOCS

	# To read on-screen, automatically paginated

	$ perldoc myscript







	# Just the "usage" sections

	$ pod2usage myscript







	# Create an HTML version

	$ pod2html myscript > myscript.html







	# Create a man page

	$ pod2man myscript > myscript.1

	for FN in 1 2 3 4 5

	do

	    somescript /tmp/rep$FNport.txt

	done

	somescript /tmp/rep${SUM}bay.txt

	export MYVAR

	export NAME=value

	export FNAME

	export SIZE

	export MAX

	...

	MAX=2048

	SIZE=64

	FNAME=/tmp/scratch

	export FNAME=/tmp/scratch

	export SIZE=64

	export MAX=2048

	...

	FNAME=/tmp/scratch2

	...

	FNAME=/tmp/stillexported

	$ set | grep MY

	# simple shell script

	echo $1

	$ cat simplest.sh

	# simple shell script

	echo ${1}

	$ ./simplest.sh you see what I mean

	you

	$ ./simplest.sh one more time

	one

	$

	$ cat tricky.sh

	echo $1 $10 ${10}

	$ ./tricky.sh I II III IV V VI VII VIII IX X XI

	I I0 X

	$

	actall *.txt

	#!/usr/bin/env bash

	# cookbook filename: chmod_all.1

	#

	# change permissions on a bunch of files

	#

	for FN in $*

	do

	    echo changing $FN

	    chmod 0750 $FN

	done

	$ ./actall abc.txt another.txt allmynotes.txt

	for FN in abc.txt another.txt allmynotes.txt

	do

	  echo changing $FN

	  chmod 0750 $FN

	done

	$ cat simpls.sh

	# simple shell script

	ls -l ${1}

	$

	$ ./simple.sh Oh the Waste

	ls: Oh: No such file or directory

	$

	$ ./simpls.sh "Oh the Waste"

	ls: Oh: No such file or directory

	ls: the: No such file or directory

	ls: Waste: No such file or directory

	$

	$ cat quoted.sh

	# note the quotes

	ls -l "${1}"

	$

	$ ./quoted.sh "Oh the Waste"

	-rw-r--r--  1 smith users 28470 2007-01-11 19:22 Oh the Waste

	$

	#

	for FN in $*

	do

	    chmod 0750 "$FN"

	done

	#!/usr/bin/env bash

	# cookbook filename: chmod_all.2

	#

	# change permissions on a bunch of files

	# with better quoting in case of filenames with blanks

	#

	for FN in "$@"

	do

	    chmod 0750 "$FN"

	done

	$ myscript these are args

	for FN in $*

	$ myscript *.mp3

	vocals.mp3

	cool music.mp3

	tophit.mp3

	$ myscript *.mp3

	$ myscript vocals.mp3 cool music.mp3 tophit.mp3

	for FN in $*

	for FN in vocals.mp3 cool music.mp3 tophit.mp3

	#!/usr/bin/env bash

	# cookbook filename: check_arg_count

	#

	# Check for the correct # of arguments:

	# Use this syntax or use: if [ $# -lt 3 ]

	if (( $# < 3 ))

	then

	   printf "%b" "Error. Not enough arguments.\n" >&2

	   printf "%b" "usage: myscript file1 op file2\n" >&2

	   exit 1

	elif (( $# > 3 ))

	then

	   printf "%b" "Error. Too many arguments.\n" >&2

	   printf "%b" "usage: myscript file1 op file2\n" >&2

	   exit 2

	else

	   printf "%b" "Argument count correct. Proceeding...\n"

	fi

	$ ./myscript myfile is copied into yourfile

	Error. Too many arguments.

	usage: myscript file1 op file2



	$ ./myscript myfile copy yourfile

	Argument count correct. Proceeding...

	for FN in "$@"

	do

	    echo changing $FN

	    chmod 0750 "$FN"

	done

	#!/usr/bin/env bash

	# cookbook filename: use_up_option

	#

	# use and consume an option

	#

	# parse the optional argument

	VERBOSE=0;

	if [[ $1 = -v ]]

	then

	    VERBOSE=1;

	    shift;

	fi

	#

	# the real work is here

	#

	for FN in "$@"

	do

	    if (( VERBOSE == 0 ))

	    then

	        echo changing $FN

	    fi

	    chmod 0750 "$FN"

	done

	FILEDIR=${1:-"/tmp"}

	cd ${HOME:=/tmp}

	$ echo ${HOME:=/tmp}

	/home/uid002

	$ unset HOME # generally not wise to do

	$ echo ${HOME:=/tmp}

	/tmp

	$ echo $HOME

	/tmp

	$ cd ; pwd

	/tmp

	$

	$ echo ${HOME=/tmp}  # no substitution needed

	/home/uid002

	$ HOME=""       # generally not wise

	$ echo ${HOME=/tmp}  # will NOT substitute



	$ unset HOME    # generally not wise

	$ echo ${HOME=/tmp}     # will substitute

	/tmp

	$ echo $HOME

	/tmp

	$

	cd ${BASE:="$(pwd)"}

	#!/usr/bin/env bash

	# cookbook filename: check_unset_parms

	#

	USAGE="usage: myscript scratchdir sourcefile conversion"

	FILEDIR=${1:?"Error. You must supply a scratch directory."}

	FILESRC=${2:?"Error. You must supply a source file."}

	CVTTYPE=${3:?"Error. ${USAGE}"}

	$ ./myscript /tmp /dev/null

	./myscript: line 5: 3: Error. usage: myscript scracthdir sourcefile conversion

	$

	CVTTYPE=${3:?"Error. $USAGE. $(rm $SCRATCHFILE)"}

	if [ -z "$3" ]

	then

	    echo "Error. $USAGE"

	    rm $SCRATCHFILE

	fi

	./myscript: line 5: 3: Error. usage: myscript scracthdir sourcefile conversion

	#!/usr/bin/env bash

	# cookbook filename: suffixer

	#

	# rename files that end in .bad to be .bash



	for FN in *.bad

	do

	    mv "${FN}" "${FN%bad}bash"

	done

	NOBAD="${FN%bad}"

	NEWNAME="${NOBAD}bash"

	mv "${FN}" "${NEWNAME}"

	mv "${FN}" "${FN/.bad/.bash}"

	MYRA=(first second third home)

	echo runners on ${MYRA[0]} and ${MYRA[2]}

	runners on first and third

	COUNT=$((COUNT + 5 + MAX * 2))

	let COUNT+=5+MAX*2

	COUNT = $((COUNT + 5)) # not what you think!

	COUNT=$((COUNT + $2 + OFFSET))

	let COUNT=COUNT+5

	let COUNT+=5

	if [ $# -lt 3 ]

	then

	    printf "%b" "Error. Not enough arguments.\n"

	    printf "%b" "usage: myscript file1 op file2\n"

	    exit 1

	fi

	if (( $# < 3 ))

	then

	    printf "%b" "Error. Not enough arguments.\n"

	    printf "%b" "usage: myscript file1 op file2\n"

	    exit 1

	fi

	if (( $# < 3 ))

	then

	    printf "%b" "Error. Not enough arguments.\n"

	    printf "%b" "usage: myscript file1 op file2\n"

	    exit 1

	elif (( $# > 3 ))

	then

	    printf "%b" "Error. Too many arguments.\n"

	    printf "%b" "usage: myscript file1 op file2\n"

	    exit 2

	else

	    printf "%b" "Argument count correct. Proceeding...\n"

	fi

	[ $result = 1 ] \

	  && { echo "Result is 1; excellent." ; exit 0;   } \

	  || { echo "Uh-oh, ummm, RUN AWAY! " ; exit 120; }

	if list; then list; [ elif list; then list; ] ... [ else list; ] fi

	if list; then list; fi

	!/usr/bin/env bash

	# cookbook filename: checkfile

	#

	DIRPLACE=/tmp

	INFILE=/home/yucca/amazing.data

	OUTFILE=/home/yucca/more.results



	if [ -d "$DIRPLACE" ]

	then

	    cd $DIRPLACE

	    if [ -e "$INFILE" ]

	    then

	        if [ -w "$OUTFILE" ]

	        then

	            doscience < "$INFILE" >> "$OUTFILE"

	        else

	            echo "can not write to $OUTFILE"

	        fi

	    else

	        echo "can not read from $INFILE"

	    fi

	else

	    echo "can not cd into $DIRPLACE"

	fi

	if [ -r $FILE -a -w $FILE ]

	if [ -r "$FN" -a \( -f "$FN" -o -p "$FN" \) ]

	if [ -z "$V1" -o -z "${V2:=YIKES}" ]

	#!/usr/bin/env bash

	# cookbook filename: checkstr

	#

	# if statement

	# test a string to see if it has any length

	#

	# use the command line argument

	VAR="$1"

	#

	if [ "$VAR" ]

	then

	    echo has text

	else

	    echo zero length

	fi

	#

	if [ -z "$VAR" ]

	then

	    echo zero length

	else

	    echo has text

	fi

	if [ -z $VAR ]

	if [ -z x -a 7 -lt 5 ]

	#!/usr/bin/env bash

	# cookbook filename: strvsnum

	#

	# the old string vs. numeric comparison dilemma

	#

	VAR1=" 05 "

	VAR2="5"

	printf "%s" "do they -eq as equal? "

	if [ "$VAR1" -eq "$VAR2" ]

	then

	    echo YES

	else

	    echo NO

	fi



	printf "%s" "do they = as equal? "

	if [ "$VAR1" = "$VAR2" ]

	then

	    echo YES

	else

	    echo NO

	fi

	$ bash strvsnum

	do they -eq as equal? YES

	do they = as equal? NO

	$

	if [[ "${MYFILENAME}" == *.jpg ]]

	shopt -s extglob

	if [[ "$FN" == *.@(jpg|jpeg) ]]

	then

	   # and so on

	$ ls

	Ludwig Van Beethoven - 01 - Allegro.ogg

	Ludwig Van Beethoven - 02 - Adagio un poco mosso.ogg

	Ludwig Van Beethoven - 03 - Rondo - Allegro.ogg

	Ludwig Van Beethoven - 04 - "Coriolan" Overture, Op. 62.ogg

	Ludwig Van Beethoven - 05 - "Leonore" Overture, No. 2 Op. 72.ogg

	$

	#!/usr/bin/env bash

	# cookbook filename: trackmatch

	#

	for CDTRACK in *

	do

	    if [[ "$CDTRACK" =~ "([[:alpha:][:blank:]]*)- ([[:digit:]]*) - (.*)$" ]]

	    then

	        echo Track ${BASH_REMATCH[2]} is ${BASH_REMATCH[3]}

	        mv "$CDTRACK" "Track${BASH_REMATCH[2]}"

	    fi

	done

	if [[ "$CDTRACK" =~ \([[:alpha:][:blank:]]*\)-\ \([[:digit:

	]]*\)\ -\ \(.*\)\$ ]]

	while (( COUNT < MAX ))

	do

	    some stuff

	    let COUNT++

	done

	while [ -z "$LOCKFILE" ]

	do

	    some things

	done

	while read lineoftext

	do

	    process $lineoftext

	done

	$ svn status bcb

	M      bcb/amin.c

	?      bcb/dmin.c

	?      bcb/mdiv.tmp

	A      bcb/optrn.c

	M      bcb/optson.c

	?      bcb/prtbout.4161

	?      bcb/rideaslist.odt

	?      bcb/x.maxc

	$

	svn status mysrc | grep '^?' | cut -c8- | \

	    while read FN; do echo "$FN"; rm -rf "$FN"; done

	svn status mysrc | \

	while read TAG FN

	do

	    if [[ $TAG == \? ]]

	    then

	        echo $FN

	        rm -rf "$FN"

	    fi

	done

	$ for (( i=0 ; i < 10 ; i++ )) ; do echo $i ; done

	for i in 1 2 3 4 5 6 7 8 9 10

	do

	    echo $i

	done

	for (( expr1 ; expr2 ; expr3 )) ; do list ; done

	for (( i=0, j=0 ; i+j < 10 ; i++, j++ ))

	do

	    echo $((i*j))

	done

	for fp in $(seq 1.0 .01 1.1)

	do

	     echo $fp; other stuff too

	done

	seq 1.0 .01 1.1 | \

	while read fp

	do

	    echo $fp; other stuff too

	done

	case $FN in

	    *.gif) gif2png $FN

	        ;;

	    *.png) pngOK $FN

	        ;;

	    *.jpg) jpg2gif $FN

	        ;;

	    *.tif | *.TIFF) tif2jpg $FN

	        ;;

	    *) printf "File not supported: %s" $FN

	        ;;

	esac

	if [[ $FN == *.gif ]]

	then

	    gif2png $FN

	elif [[ $FN == *.png ]]

	then

	    pngOK $FN

	elif [[ $FN == *.jpg ]]

	then

	    jpg2gif $FN

	elif [[ $FN == *.tif || $FN == *.TIFF ]]

	then

	    tif2jpg $FN

	else

	    printf "File not supported: %s" $FN

	fi

	dashes        # would print out 72 dashes

	dashes 50     # would print out 50 dashes

	dashes -c= 50     # would print out 50 equal signs

	dashes -cx    # would print out 72 x characters

	#!/usr/bin/env bash

	# cookbook filename: dashes

	#

	# dashes - print a line of dashes

	#

	# options: # how many (default 72)

	# -c X use char X instead of dashes

	#

	

	LEN=72

	CHAR='-'

	while (( $# > 0 ))

	do

	    case $1 in

	        [0-9]*) LEN=$1

	            ;;

	        -c) shift;

	               CHAR=${1:--}

	            ;;

	        *)  printf 'usage: %s [-c X] [#]\n' $(basename $0) >&2

	            exit 2

	            ;;

	    esac

	    shift

	done

	#

	# more...

	#!/usr/bin/env bash

	# cookbook filename: dbinit.1

	#

	DBLIST=$(sh ./listdb | tail +2)

	select DB in $DBLIST

	do

	    echo Initializing database: $DB

	    mysql -uuser -p $DB <myinit.sql

	done

	$ ./dbinit

	1) testDB

	2) simpleInventory

	3) masterInventory

	4) otherDB

	#? 2

	Initializing database: simpleInventory

	#?

	$

	#!/usr/bin/env bash

	# cookbook filename: dbinit.2

	#

	DBLIST=$(sh ./listdb | tail +2)



	PS3="0 inits >"



	select DB in $DBLIST

	do

	    if [ $DB ]

	    then

	        echo Initializing database: $DB



	        PS3="$((i++)) inits >"



	        mysql -uuser -p $DB <myinit.sql

	    fi

	done

	$

	#!/usr/bin/env bash

	# cookbook filename: rpncalc

	#

	# simple RPN command line (integer) calculator

	#

	# takes the arguments and computes with them

	# of the form a b op

	# allow the use of x instead of *

	#

	# error check our argument counts:

	if [ \( $# -lt 3 \) -o \( $(($# % 2)) -eq 0 \) ]

	then

	    echo "usage: calc number number op [ number op ] ..."

	    echo "use x or '*' for multiplication"

	    exit 1

	fi



	ANS=$(($1 ${3//x/*} $2))

	shift 3

	while [ $# -gt 0 ]

	do

	    ANS=$((ANS ${2//x/*} $1))

	    shift 2

	done

	echo $ANS

	$(($# % 2)) -eq 0

	# cookbook filename: func_calc



	# Trivial command line calculator

	function calc

	{

	    awk "BEGIN {print \"The answer is: \" $* }";

	}

	$ calc 2 + 3 + 4

	The answer is: 9



	$ calc 2 + 3 + 4.5

	The answer is: 9.5

	$ calc (2+2-3)*4

	-bash: syntax error near unexpected token `2+2-3'

	$ calc '(2+2-3)*4'

	The answer is: 4

	

	$ calc \(2+2-3\)\*4

	The answer is: 4



	$ calc '(2+2-3)*4.5'

	The answer is: 4.5

	$ grep printf *.c

	both.c:    printf("Std Out message.\n", argv[0], argc-1);

	both.c:    fprintf(stderr, "Std Error message.\n", argv[0], argc-1);

	good.c:    printf("%s: %d args.\n", argv[0], argc-1);

	somio.c:        // we'll use printf to tell us what we

	somio.c:        printf("open: fd=%d\n", iod[i]);

	$

	$ grep printf ../lib/*.c ../server/*.c ../cmd/*.c */*.c

	$ grep -h printf *.c

	  printf("Std Out message.\n", argv[0], argc-1);

	  fprintf(stderr, "Std Error message.\n", argv[0], argc-1);

	  printf("%s: %d args.\n", argv[0], argc-1);

	     // we'll use printf to tell us what we

	     printf("open: fd=%d\n", iod[i]);

	$

	$ grep -l printf *.c

	both.c

	good.c

	somio.c

	$ rm -i $(grep -l 'This file is obsolete' * )

	$ grep -q findme bigdata.file

	$ if [ $? -eq 0 ] ; then echo yes ; else echo nope ; fi

	nope

	$

	$ grep findme bigdata.file >/dev/null

	$ if [ $? -eq 0 ] ; then echo yes ; else echo nope ; fi

	nope

	$

	 $ grep -i error logfile.msgs

	$ some pipeline | of commands | grep

	$ gcc bigbadcode.c 2>&1 | grep -i error

	$ grep -i johnson mail/*

	... too much output to think about; there are lots of Johnsons in the world ...

	$ !! | grep -i robert

	grep -i johnson mail/* | grep -i robert

	... more manageable output ...

	$ !! | grep -i "the bluesman"

	grep -i johnson mail/* | grep -i robert | grep -i "the bluesman"

	Robert M. Johnson, The Bluesman <rmj@noplace.org>

	...

	error on Jan 01: not a decimal number

	error on Feb 13: base converted to Decimal

	warning on Mar 22: using only decimal numbers

	error on Dec 16 : the actual message you wanted

	error on Jan 01: not a decimal number

	...

	$ grep -i dec logfile | grep -vi decimal

	$ grep -i dec logfile | grep -vi decimal | grep -vi decimate

	$ grep 'Dec [0-9][0-9]' logfile

	$ grep 'Dec [0-9 ][0-9]' logfile

	$ grep '[0-9]\{3\}-\{0,1\}[0-9]\{2\}-\{0,1\}[0-9]\{4\}' datafile

	[0-9]\{3\} -\{0,1\} [0-9]\{2\} -\{0,1\} [0-9]\{4\}

	$ zgrep 'search term' /var/log/messages*

	$ zcat /var/log/messages.1.gz

	$ awk '{print $1}' myinput.file

	$ awk '{print $1}' < myinput.file

	$ cat myinput.file | awk '{print $1}'

	$ ls -l | awk '{print $1, $NF}'

	total 151130

	-rw-r--r-- add.1

	drwxr-xr-x art

	drwxr-xr-x bin

	-rw-r--r-- BuddyIcon.png

	drwxr-xr-x CDs

	drwxr-xr-x downloads

	drwxr-sr-x eclipse

	...	

	$

	drwxr-xr-x 2 username group      176 2006-10-28 20:09 bin

	  $ awk '{

	>      for (i=NF; i>0; i--) {

	>          printf "%s ", $i;

	>    }

	>    printf "\n"

	> }'

	$ awk '{for (i=NF; i>0; i--) {printf "%s ", $i;} printf "\n" }'

	$ ls -l | awk '{sum += $5} END {print sum}'

	-rw-r--r-- 1 albing users 267 2005-09-26 21:26 lilmax

	$ ls -l | grep -v '^total' | awk '{sum += $5} END {print sum}'

	$ ls -l | awk '/^total/{getline} {sum += $5} END {print sum}'

	#

	# cookbook filename: asar.awk

	#

	NF < 7 {

	           user[$3]++

	    }

	END {

	          for (i in user)	

	          {

	               printf "%s owns %d files\n", i, user[i]

	          }

	   }

	$ ls -lR /usr/local | awk -f asar.awk

	bin owns 68 files

	albing owns 1801 files

	root owns 13755 files

	man owns 11491 files

	$

	 user[$3]++

	#

	# cookbook filename: hist.awk

	#

	function max(arr, big)

	{

	    big = 0;

	    for (i in user)

	    {

	        if (user[i] > big) { big=user[i];}

	    }

	    return big

	}



	NF > 7{

	      user[$3]++

	   }

	EN {

	      # for scaling

	      maxm = max(user);

	      for (i in user)

	      {

	      #printf "%s owns %d files\n", i, user[i]

	      scaled = 60 * user[i] / maxm ;

	      printf "%-10.10s [%8d]:", i, user[i]

	      for (i=0; i<scaled; i++) {

	          printf "#";

	      }

	      printf "\n";

	   }

	}

	$ ls -lR /usr/local |  awk -f hist.awk

	bin       [      68]:#

	albing    [    1801]:#######

	root      [   13755]:##################################################

	man       [   11491]:##########################################

	$

	$ cat para.awk

	/keyphrase/ { flag=1 }

	{ if (flag == 1) { print $0 } }

	/^$/ { flag=0 }

	$

	$ awk -f para.awk < searchthis.txt

	/^[:blank:]*$/ { flag=0 }

	$ sort file1.txt file2.txt myotherfile.xyz

	$ somecommands | sort

	$ sort -r

	$ sort -f

	$ sort --ignore-case

	$ sort somedata

	2

	200

	21

	250

	$

	$ sort -n somedata

	2

	21

	200

	250

	$

	$ cut -d':' -f7 /etc/passwd | sort | uniq -c | sort -rn

	     20 /bin/sh

	     10 /bin/false

	      2 /bin/bash

	      1 /bin/sync

	cut -d':' -f7 /etc/passwd | sort -u

	$ sort -t. -n +3.0 ipaddr.list

	10.0.0.2

	192.168.0.2	

	192.168.0.4

	10.0.0.5

	192.168.0.12

	10.0.0.20

	$

	$ sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n ipaddr.list

	10.0.0.2

	10.0.0.5

	10.0.0.20

	192.168.0.2

	192.168.0.4

	192.168.0.12

	$

	$ sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n ipaddr.list

	$ ps -l | cut -c12-15

	PID

	5391

	7285

	7286

	$

	$ ps -elf | cut -c58-

	(output not shown)

	$ cut -d'#' -f2 < ipaddr.list

	$ awk -F'#' '{print $2}' < ipaddr.list

	$ cat delimited_data

	Line [l1].

	Line [l2].

	Line [l3].



	$ cut -d'[' -f2 delimited_data | cut -d']' -f1

	l1

	l2

	l3

	$ somesequence | sort -u

	$ somesequence > myfile

	$ uniq myfile

	$ tar cf tarball_name.tar directory_of_files

	$ gzip tarball_name.tar

	$ tar czf tarball_name.tgz directory_of_files

	$ file what_is_this.*

	what_is_this.1: GNU tar archive

	what_is_this.2: gzip compressed data, from Unix



	$ gunzip what_is_this.2

	gunzip: what_is_this.2: unknown suffix -- ignored



	$ mv what_is_this.2 what_is_this.2.gz



	$ gunzip what_is_this.2.gz



	$ file what_is_this.2

	what_is_this.2: GNU tar archive

	$ tar tf some.tar | awk -F/ '{print $1}' | sort -u

	$ tr ';' ',' <be.fore >af.ter

	$ tr ';:.!?' ',' <other.punct >commas.all

	$ tr 'A-Z' 'a-z' <be.fore >af.ter

	$ tr '[:upper:]' '[:lower:]' <be.fore >af.ter

	$ cat /tmp/joke

	Q: Why did the chicken cross the road?

	A: To get to the other side.



	$ tr 'A-Za-z' 'N-ZA-Mn-za-m' < /tmp/joke

	D: Jul qvq gur puvpxra pebff gur ebnq?

	N: Gb trg gb gur bgure fvqr.



	$ tr 'A-Za-z' 'N-ZA-Mn-za-m' < /tmp/joke | tr 'A-Za-z' 'N-ZA-Mn-za-m'

	Q: Why did the chicken cross the road?

	A: To get to the other side.

	$ tr -d '\r' <file.dos >file.txt

	$ tr '\221\222\223\224\226\227' '\047\047""--' <odd.txt >plain.txt

A few mail clients send curved quotes using the Windows-1252 codes but mark the text as ISO-8859-1 causing problems for decoders that do not make the dubious assumption that C1 control codes in ISO-8859-1 text were meant to be Windows-1252 printable characters.

	$ wc data_file

	       5     15       60 data_file



	# Lines only

	$ wc -l data_file

	       5 data_file



	# Words only

	$ wc -w data_file

	      15 data_file



	# Characters (often the same as bytes) only

	$ wc -c data_file

	      60 data_file



	# Note 60B

	$ ls -l data_file

	-rw-r--r--  1 jp  users   60B Dec    6 03:18 data_file

	data_file_lines=$(wc -l "$data_file")	

	data_file_lines=$(wc -l "$data_file" | awk '{print $1}')

	$ fmt mangled_text

	$ fmt 55 60 mangled_text

	export LESS="--LONG-PROMPT --LINE-NUMBERS --ignore-case --QUIET"

	$ ./lesspipe.sh

	LESSOPEN="|./lesspipe.sh %s"

	export LESSOPEN

gzip, compress, bzip2, zip, rar, tar, nroff, ar archive, pdf, ps, dvi, shared library, executable, directory, RPM, Microsoft Word, OpenOffice 1.x and OASIS (OpenDocument) formats, Debian, MP3 files, image formats (png, gif, jpeg, tiff, …), utf-16 text, iso images and filesystems on removable media via /dev/xxx

	$ find . -name '*.mp3' -print -exec mv '{}' ~/songs \;

	$ find . -name '*.mp3' -print0 | xargs -i -0 mv '{}' ~/songs

	$ locate P1100087.JPG PC220010.JPG PA310075.JPG PA310076.JPG | xargs -i cp '{}' .

	$ find . -follow -name '*.mp3' -print0 | xargs -i -0 mv '{}' ~/songs

	$ find . -follow -iname '*.mp3' -print0 | xargs -i -0 mv '{}' ~/songs

	$ find . -name '*.jpg' -print

	$ find . -name '*.[Jj][Pp][Gg]' -print

	find . -name '*.jpg' -mtime +90 -print

	$ find . -mtime +7 -a -mtime -14 -print

	$ find . -mtime +14 -name '*.text' -o \( -mtime -14 -name '*.txt' \) -print

	$ find . -name '*java*' -print

	$ find . -type d -name '*java*' -print

	find . -size +3000k -print

	grep -i portend *.txt

	grep -i portend */*.txt

	find . -name '*.txt' -exec grep -Hi portend '{}' \;

	$ locate apropos

	/usr/bin/apropos

	/usr/share/man/de/man1/apropos.1.gz

	/usr/share/man/es/man1/apropos.1.gz

	/usr/share/man/it/man1/apropos.1.gz

	/usr/share/man/ja/man1/apropos.1.gz

	/usr/share/man/man1/apropos.1.gz

	$ source myfile

	LS=$(type -P ls)

	[ -x $LS ] && $LS

	

	# --OR--

	

	LS=$(type -P ls)

	if [ -x $LS ]; then

	   : commands involving $LS here

	fi

	for path in ${PATH//:/ }; do

	    [ -x "$path/ls" ] && $path/ls

	done

	

	# --OR--

	

	for path in ${PATH//:/ } /opt/foo/bin /opt/bar/bin; do

	    [ -x "$path/ls" ] && $path/ls

	done

	for file in /usr/local/bin/inputrc /etc/inputrc ~/.inputrc; do

	       [ -f "$file" ] && bind -f "$file" && break # Use the first one found 

	done

	for path in ${PATH//:/ }; do

	    if [ -x "$path/screen" ]; then

	        # If screen(1) exists and is executable:

	        for file in /opt/bin/settings/run_screen ~/settings/run_screen; do

	            [ -x "$file" ] && $file && break # Execute the first one found

	        done

	    fi

	done

	nohup mydaemonscript 0<&-1>/dev/null 2>&1 &

	nohup mydaemonscript >>/var/log/myadmin.log 2>&1 <&-  &

	$ cat myprefs.cfg

	SCRATCH_DIR=/var/tmp

	IMG_FMT=png

	SND_FMT=ogg

	$

	#

	# use the user prefs

	#

	source $HOME/myprefs.cfg

	cd ${SCRATCH_DIR:-/tmp}

	echo You prefer $IMG_FMT image files

	echo You prefer $SND_FMT sound files

	. $HOME/myprefs.cfg

	$include $HOME/myprefs.cfg

	# In config file

	VERBOSE=0                # '' for off, 1 for on

	SSH_USER='jbagadonutz@'  # Note trailing @, set to '' to use the current user

	# In script

	[ "$VERBOSE" ] || echo "Verbose msg from $) goes to STDERR" >&2

	[...]

	ssh $SSH_USER$REMOTE_HOST [...]

	# If $SSH_USER is set and doesn't have a trailing @ add it:

	[ -n "$SSH_USER" -a "$SSH_USER" = "${SSH_USER%@}" ] && SSH_USER="$SSH_USER@"

	ssh ${SSH_USER:+${SSH_USER}@}${REMOTE_HOST} [...]

	function usage ()

	{

		printf "usage: %s [ -a | - b ] file1 ... filen\n" $0 > &2

	}

	if [ $# -lt 1]

	then

		usage

	fi

	function usage ()

	{

		printf "usage: %s [ -a | - b ] file1 ... filen\n" $0 > &2

	}





	function usage {

		printf "usage: %s [ -a | - b ] file1 ... filen\n" $0 > &2

	}





	usage ( )

	{

		printf "usage: %s [ -a | - b ] file1 ... filen\n" $0 > &2

	}





	usage ( ) {

		printf "usage: %s [ -a | - b ] file1 ... filen\n" $0 > &2

	}

	# define the function:

	function max ()

	{ ... }

	#

	# call the function:

	#

	max   128   $SIM

	max  $VAR  $CNT

	# cookbook filename: func_max.1



	# define the function:

	function max ()

	{

		local HIDN

		if [ $1 -gt $2 ]

		then

			BIGR=$1

		else

			BIGR=$2

		fi

		HIDN=5

	}

	# call the function:

	max 128 $SIM

	# use the result:

	echo $BIGR

	# cookbook filename: func_max.2



	# define the function:

	function max ()

	{

		if [ $1 -gt $2 ]

		then

		echo $1

		else

		echo $2

		fi

	}

	# call the function:

	BIGR=$(max 128 $SIM)

	# use the result

	echo $BIGR

	# NetBSD

	$ trap -l

	 1) SIGHUP    2)   SIGINT      3) SIGQUIT    4) SIGILL

	 5) SIGTRAP   6)   SIGABRT     7) SIGEMT     8) SIGFPE

	 9) SIGKILL   10)  SIGBUS     11) SIGSEGV   12) SIGSYS

	 13) SIGPIPE  14)  SIGALRM    15) SIGTERM   16) SIGURG

	 17) SIGSTOP  18)  SIGTSTP    19) SIGCONT   20) SIGCHLD

	 21) SIGTTIN  22)  SIGTTOU    23) SIGIO     24) SIGXCPU

	 25) SIGXFSZ  26)  SIGVTALRM  27) SIGPROF   28) SIGWINCH

	 29) SIGINFO  30)  SIGUSR1    31) SIGUSR2   32) SIGPWR

	 # Linux

	 $ trap -l

	   1) SIGHUP        2) SIGINT        3)  SIGQUIT      4) SIGILL

	   5) SIGTRAP       6) SIGABRT       7)  SIGBUS       8) SIGFPE

	   9) SIGKILL      10) SIGUSR1      11) SIGSEGV      12) SIGUSR2

	  13) SIGPIPE      14) SIGALRM      15) SIGTERM      17) SIGCHLD

	  18) SIGCONT      19) SIGSTOP      20) SIGTSTP      21) SIGTTIN

	  22) SIGTTOU      23) SIGURG       24) SIGXCPU      25) SIGXFSZ

	  26) SIGVTALRM    27) SIGPROF      28) SIGWINCH     29) SIGIO

	  30) SIGPWR       31) SIGSYS       33) SIGRTMIN     34) SIGRTMIN+1

	  35) SIGRTMIN+2   36) SIGRTMIN+3   37) SIGRTMIN+4   38) SIGRTMIN+5

	  39) SIGRTMIN+6   40) SIGRTMIN+7   41) SIGRTMIN+8   42) SIGRTMIN+9

	  43) SIGRTMIN+10  44) SIGRTMIN+11  45) SIGRTMIN+12  46) SIGRTMIN+13

	  47) SIGRTMIN+14  48) SIGRTMIN+15  49) SIGRTMAX-15  50) SIGRTMAX-14

	  51) SIGRTMAX-13  52) SIGRTMAX-12  53) SIGRTMAX-11  54) SIGRTMAX-10

	  55) SIGRTMAX-9   56) SIGRTMAX-8   57) SIGRTMAX-7   58) SIGRTMAX-6

	  59) SIGRTMAX-5   60) SIGRTMAX-4   61) SIGRTMAX-3   62) SIGRTMAX-2

	  63) SIGRTMAX-1   64) SIGRTMAX

	alias ls='ls -a'

	alias h='ls $HOME'

	alias h='ls ~'

	...

	alias h='ls /home/youracct'

	...

	unalias h

	$ alias echo='echo ~~~'



	$ echo test

	~~~ test



	$ \echo test

	test



	$ builtin echo test

	test



	$ type echo

	echo is aliased to `echo ~~~'



	$ unalias echo



	$ type echo

	echo is a shell builtin



	$ type -a echo

	echo is a shell builtin

	echo is /bin/echo



	$ echo test

	test

	function cd ()

	{

		if [[ $1 = "..." ]]

		then

			builtin cd ../..

		else

			builtin cd $1

		fi

	}

	# Setting environment variables can be helpful in scripts:

	$ STRICT_ISO_8601='%Y-%m-%dT%H:%M:%S%z'   # http://greenwichmeantime.com/info/iso.htm

	$ ISO_8601='%Y-%m-%d %H:%M:%S %Z'        # Almost ISO-8601, but more human-readable

	$ ISO_8601_1='%Y-%m-%d %T %Z'           # %T is the same as %H:%M:%S

	$ DATEFILE='%Y%m%d%H%M%S'               # Suitable for use in a file name



	$ date "+$ISO_8601"

	2006-05-08 14:36:51 CDT



	gawk "BEGIN {print strftime(\"$ISO_8601\")}"

	2006-12-07 04:38:54 EST



	# Same as previous $ISO_8601

	$ date '+%Y-%m-%d %H:%M:%S %Z'

	2006-05-08 14:36:51 CDT



	$ date -d '2005-11-06' "+$ISO_8601"

	2005-11-06 00:00:00 CST



	$ date "+Program starting at: $ISO_8601"

	Program starting at: 2006-05-08 14:36:51 CDT



	$ printf "%b" "Program starting at: $(date '+$ISO_8601')\n"

	Program starting at: $ISO_8601



	$ echo "I can rename a file like this: mv file.log file_$(date +$DATEFILE).log"

	I can rename a file like this: mv file.log file_20060508143724.log

	#!/usr/bin/env bash

	# cookbook filename: default_date



	# Use Noon time to prevent a script running around midnight and a clock a

	# few seconds off from causing off by one day errors.

	START_DATE=$(date -d 'last week Monday 12:00:00' '+%Y-%m-%d')



	while [ 1 ]; do

	    printf "%b" "The starting date is $START_DATE, is that correct? (Y/new date)"

	    read answer



	    # Anything other than ENTER, "Y" or "y" is validated as a new date

	    # could use "[Yy]*" to allow the user to spell out "yes"...

	    # validate the new date format as: CCYY-MM-DD

	    case "$answer" in

	       [Yy]) break

	            ;;

	        [0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])

	            printf "%b" "Overriding $START_DATE with $answer\n"

	            START_DATE="$answer"

	            ;;



	        *)   printf "%b" "Invalid date, please try again...\n"

	            ;;



	    esac

	done



	END_DATE=$(date -d "$START_DATE +7 days" '+%Y-%m-%d')



	echo "START_DATE: $START_DATE"

	echo "END_DATE:   $END_DATE"

	$ date '+%Y-%m-%d %H:%M:%S %z'

	2005-11-05 01:03:00 -0500



	$ date -d 'today' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-05 01:04:39 -0500



	$ date -d 'yesterday' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-04 01:04:48 -0500



	$ date -d 'tomorrow' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-06 01:04:55 -0500



	$ date -d 'Monday' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-07 00:00:00 -0500



	$ date -d 'this Monday' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-07 00:00:00 -0500



	$ date -d 'last Monday' '+%Y-%m-%d %H:%M:%S %z'

	2005-10-31 00:00:00 -0500



	$ date -d 'next Monday' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-07 00:00:00 -0500

	

	$ date -d 'last week' '+%Y-%m-%d %H:%M:%S %z'

	2005-10-29 01:05:24 -0400



	$ date -d 'next week' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-12 01:05:29 -0500



	$ date -d '2 weeks' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-19 01:05:42 -0500



	$ date -d '-2 weeks' '+%Y-%m-%d %H:%M:%S %z'

	2005-10-22 01:05:47 -0400



	$ date -d '2 weeks ago' '+%Y-%m-%d %H:%M:%S %z'

	2005-10-22 01:06:00 -0400



	$ date -d '+4 days' '+%Y-%m-%d %H:%M:%S %z'

	2005-11-09 01:06:23 -0500



	$ date -d '-6 days' '+%Y-%m-%d %H:%M:%S %z'

	2005-10-30 01:06:30 -0400



	$ date -d '2000-01-01 +12 days' '+%Y-%m-%d %H:%M:%S %z'

	2000-01-13 00:00:00 -0500



	$ date -d '3 months 1 day' '+%Y-%m-%d %H:%M:%S %z'

	2006-02-06 01:03:00 -0500

	$ date '+%a %Y-%m-%d'

	Sat 2005-11-05



	$ date -d 'today' '+%a %Y-%m-%d'

	Sat 2005-11-05



	$ date -d 'Saturday' '+%a %Y-%m-%d'

	Sat 2005-11-05



	$ date -d 'last Saturday' '+%a %Y-%m-%d'

	Sat 2005-10-29



	$ date -d 'this Saturday' '+%a %Y-%m-%d'

	Sat 2005-11-05

	# "Now" is easy

	$ date '+%s'

	1131172934



	# Some other time needs the non-standard -d

	$ date -d '2005-11-05 12:00:00 +0000' '+%s'

	1131192000

	$ perl -e 'print time, qq(\n);'

	1154158997



	# Same as above

	$ perl -e 'use Time::Local; print timelocal(localtime()) . qq(\n);'

	1154158997



	$ perl -e 'use POSIX qw(strftime); print strftime("%s", localtime()) . qq(\n);'

	1154159097

	# The given time is in local time

	$ perl -e 'use Time::Local; print timelocal("49", "59", "06", "05", "10", "105") .

	.qq(\n);'

	1131191989



	# The given time is in UTC time

	$ perl -e 'use Time::Local; print timegm("49", "59", "06", "05", "10", "105") .

	qq(\n);'

	1131173989

	EPOCH='1131173989'



	$ date -d "1970-01-01 UTC $EPOCH seconds" +"%Y-%m-%d %T %z"

	2005-11-05 01:59:49 -0500



	$ date --utc --date "1970-01-01 $EPOCH seconds" +"%Y-%m-%d %T %z"

	2005-11-05 06:59:49 +0000

	EPOCH='1131173989'



	$ perl -e "print scalar(gmtime($EPOCH)), qq(\n);" # UTC

	Sat Nov 5 06:59:49 2005



	$ perl -e "print scalar(localtime($EPOCH)), qq(\n);" # Your local time

	Sat Nov 5 01:59:49 2005



	$ perl -e "use POSIX qw(strftime); print strftime('%Y-%m-%d %H:%M:%S',

	localtime($EPOCH)), qq(\n);"

	2005-11-05 01:59:49

	# Yesterday at this same time (note subtraction)

	$ perl -e "use POSIX qw(strftime); print strftime('%Y-%m-%d', localtime(time -

	86400)), qq(\n);"



	# Tomorrow at this same time (note addition)

	$ perl -e "use POSIX qw(strftime); print strftime('%Y-%m-%d', localtime(time +

	86400)), qq(\n);"

	CORRECTION='172800' # 2 days worth of seconds



	# Code to extract the date portion from the data

	# into $bad_date go here



	# Suppose it's this:

	bad_date='Jan 2 05:13:05' # syslog formated date



	# Convert to Epoch using GNU date

	bad_epoch=$(date -d "$bad_date" '+%s')



	# Apply correction

	good_epoch=$(( bad_epoch + $CORRECTION ))



	# Make corrected date human-readable

	good_date=$(date -d "1970-01-01 UTC $good_epoch seconds") # GNU Date

	good_date_iso=$(date -d "1970-01-01 UTC $good_epoch seconds" +'%Y-%m-%d %T') # GNU

	Date



	echo "bad_date:        $bad_date"

	echo "bad_epoch:       $bad_epoch"

	echo "Correction:      +$CORRECTION"

	echo "good_epoch:      $good_epoch"

	echo "good_date:       $good_date"

	echo "good_date_iso:   $good_date_iso"



	# Code to insert the $good_date back into the data goes here

	# Vixie Cron

	# Min Hour DoM Mnth DoW Program

	# 0-59 0-23 1-31 1-12 0-7



	# Run the first Wednesday @ 23:00

	00 23 1-7 * Wed [ "$(date '+%a')" == "Wed" ] && /path/to/command args to command



	# Run the second Thursday @ 23:00

	00 23 8-14 * Thu [ "$(date '+%a')" == "Thu" ] && /path/to/command



	# Run the third Friday @ 23:00

	00 23 15-21 * Fri [ "$(date '+%a')" == "Fri" ] && /path/to/command



	# Run the fourth Saturday @ 23:00

	00 23 22-27 * Sat [ "$(date '+%a')" == "Sat" ] && /path/to/command



	# Run the fifth Sunday @ 23:00

	00 23 28-31 * Sun [ "$(date '+%a')" == "Sun" ] && /path/to/command

	$ cal 10 2006

	   October 2006

	 S  M  Tu   W  Th   F   S

	 1  2   3   4   5   6   7

	 8  9  10  11  12  13  14

	15 16  17  18  19  20  21

	22 23  24  25  26  27  28

	29 30  31

 1 #!/usr/bin/env bash

 2 # cookbook filename: dash

 3 # dash - print a line of dashes

 4 # options: # how many (default 72)

 5 #         -c X use char X instead of dashes

 6 #

 7 function usagexit ( )

 8 {

 9     printf "usage: %s [-c X] [#]\n" $(basename $0)

10     exit 2

11 } >&2

12 LEN=72

13 CHAR='-'

14 while (( $# > 0 ))

15 do

16     case $1 in

17     [0-9]*) LEN=$1;;

18     -c) shift

19         CHAR=$1;;

20     *) usagexit;;

21     esac

22     shift

23 done



24 if (( LEN > 4096 ))

25 then

26     echo "too large" >&2

27     exit 3



28 fi

29 # build the string to the exact length

30 DASHES=""

31 for ((i=0; i<LEN; i++))

32 do

33     DASHES="${DASHES}${CHAR}"

34 done

35 printf "%s\n" "$DASHES"

	$ ls *.jpg | mkalbum rugbymatch

Figure 12-1: Sample mkalbum web page

 1 #!/usr/bin/env bash

 2 # cookbook filename: mkalbum

 3 # mkalbum - make an html "album" of a pile of photo files.

 4 # ver. 0.2

 5 #

 6 # An album is a directory of html pages.

 7 # It will be created in the current directory.

 8 #

 9 # An album page is the html to display one photo, with

10 # a title that is the filename of the photo, along with

11 # hyperlinks to the first, previous, next, and last photos.

12 #

13 # ERROUT

14 ERROUT( )

15 {

16     printf "%b" "$@"

17 } >&2

18

19 #

20 # USAGE

21 USAGE( )

22 {

23     ERROUT "usage: %s <newdir>\n" $(basename $0)

24 }

25

26 # EMIT(thisph, startph, prevph, nextph, lastph)

27 EMIT( )

28 {

29   THISPH="../$1"

30   STRTPH="${2%.*}.html"

31   PREVPH="${3%.*}.html"

32   NEXTPH="${4%.*}.html"

33   LASTPH="${5%.*}.html"

34   if [ -z "$3" ]

35   then

36      PREVLINE='<TD> Prev </TD>'

37   else

38      PREVLINE='<TD> <A HREF="'$PREVPH'"> Prev </A> </TD>'

39   fi

40   if [ -z "$4" ]

41   then

42      NEXTLINE='<TD> Next </TD>'

43   else

44      NEXTLINE='<TD> <A HREF="'$NEXTPH'"> Next </A> </TD>'

45   fi

46 cat <<EOF

47 <HTML>

48 <HEAD><TITLE>$THISPH</TITLE></HEAD>

49 <BODY>

50   <H2>$THISPH</H2>

51 <TABLE WIDTH="25%">

52   <TR>

53   <TD> <A HREF="$STRTPH"> First </A> </TD>

54   $PREVLINE

55   $NEXTLINE

56   <TD> <A HREF="$LASTPH"> Last </A> </TD>

57   </TR>

58 </TABLE>

59   <IMG SRC="$THISPH" alt="$THISPH"

60   BORDER="1" VSPACE="4" HSPACE="4"

61   WIDTH="800" HEIGHT="600"/>

62 </BODY>

63 </HTML>

64 EOF

65 }

66

67 if (( $# != 1 ))

68 then

69     USAGE

70     exit -1

71 fi

72 ALBUM="$1"

73 if [ -d "${ALBUM}" ]

74 then

75     ERROUT "Directory [%s] already exists.\n" ${ALBUM}

76     USAGE

77     exit -2

78 else

79     mkdir "$ALBUM"

80 fi

81 cd "$ALBUM"

82

83 PREV=""

84 FIRST=""

85 LAST="last"

86

87 while read PHOTO

88 do

89      # prime the pump

90      if [ -z "${CURRENT}" ]

91      then

92          CURRENT="$PHOTO"

93          FIRST="$PHOTO"

94          continue

95      fi

96

97      PHILE=$(basename "${CURRENT}")

98      EMIT "$CURRENT" "$FIRST" "$PREV" "$PHOTO" "$LAST" > "${PHILE%.*}.html"

99

100 1   # set up for next iteration

101     PREV="$CURRENT"

102     CURRENT="$PHOTO"

103

104 done

105

106 PHILE=$(basename ${CURRENT})

107 EMIT "$CURRENT" "$FIRST" "$PREV" "" "$LAST" > "${PHILE%.*}.html"

108

109 # make the symlink for "last"

110 ln -s "${PHILE%.*}.html" ./last.html

111

112 # make a link for index.html

113 ln -s "${FIRST%.*}.html" ./index.html

114

 1 #!/usr/bin/env bash

 2 # cookbook filename: load_mp3

 3 # Fill up my mp3 player with as many songs as will fit.

 4 # N.B.: This assumes that the mp3 player is mounted on /media/mp3

 5 #

 6

 7 #

 8 # determine the size of a file

 9 #

10 function FILESIZE ( )

11 {

12     FN=${1:-/dev/null}

13     if [[ -e $FN ]]

14     then

15        # FZ=$(ls -s $FN | cut -d ' ' -f 1)

16             set -- $(ls -s "$FN")

17             FZ=$1

18         fi

19 }

20

21 #

22 # compute the freespace on the mp3 player

23 #

24 function FREESPACE

25 {

26     # FREE=$(df /media/mp3 | awk '/^\/dev/ {print $4}')

27     set -- $(df /media/mp3 | grep '^/dev/')

28     FREE=$4

29 }

30

31 # subtract the (given) filesize from the (global) freespace

32 function REDUCE ( )

33 (( FREE-=${1:-0}))

34

35 #

36 # main:

37 #

38 let SUM=0

39 let COUNT=0

40 export FZ

41 export FREE

42 FREESPACE

43 find . -name '*.mp3' -print | \

44 (while read PATHNM

45 do

46    FILESIZE "$PATHNM"

47    if ((FZ <= FREE))

48    then

49         echo loading $PATHNM

50       cp "$PATHNM" /media/mp3

51       if (( $? == 0 ))

52       then

53           let SUM+=FZ

54           let COUNT++

55           REDUCE $FZ

56       else

57           echo "bad copy of $PATHNM to /media/mp3"

58           rm -f /media/mp3/$(basename "$PATHNM")

59           # recompute because we don't know how far it got

60           FREESPACE

61       fi

62       # any reason to go on?

63       if (( FREE <= 0 ))

64       then

65           break

66       fi

67    else

68        echo skipping $PATHNM

69    fi

70 done

71 printf "loaded %d songs (%d blocks)" $COUNT $SUM

72 printf " onto /media/mp3 (%d blocks free)\n" $FREE

73 )

74 # end of script

 1 #!/usr/bin/env bash

 2 # cookbook filename: cdscript

 3 # cdscript - prep and burn a CD from a dir.

 4 #

 5 # usage: cdscript dir [ cddev ]

 6 #	

 7 if [[ $# < 1 || $# > 2 ]]

 8 then

 9     echo 'usage: cdscript dir [ cddev ]'

10     exit 2

11 fi

12

13 # set the defaults

14 RCDIR=$1

15 # your device might be "ATAPI:0,0,0" or other digits

16 CDDEV=${2:-"ATAPI:0,0,0"}

17 ISOIMAGE=/tmp/cd$$.iso

18

19 echo "building ISO image..."

20 #

21 # make the ISO fs image

22 #

23 mkisofs $ISOPTS -A "$(cat ~/.cdAnnotation)" \

24     -p "$(hostname)" -V "$(basename $SRCDIR)" \

25     -r -o "$ISOIMAGE" $SRCDIR

26 STATUS=$?

27 if [ $STATUS -ne 0 ]

28 then

29     echo "Error. ISO image failed."

30     echo "Investigate then remove $ISOIMAGE"

31     exit $STATUS

32 fi

33

34 echo "ISO image built; burning to cd..."

35 exit

36

37 # burn the CD

38 SPD=8

39 OPTS="-eject -v fs=64M driveropts=burnproof"

40 cdrecord $OPTS -speed=$SPD dev=${CDDEV} $ISOImage

41 STATUS=$?

42 if [ $STATUS -ne 0 ]

43 then

44     echo "Error. CD Burn failed."

45     echo "Investigate then remove $ISOIMAGE"

46     exit $STATUS

47 fi

48

49 rm -f $ISOIMAGE

50 echo "Done."

	17 ISOIMAGE=/tmp/cd$$.iso

 1 #!/usr/bin/env bash

 2 # cookbook filename: oodiff

 3 # oodiff -- diff the CONTENTS of two OpenOffice.org files

 4 # works only on .odt files

 5 #

 6 function usagexit ( )

 7 {

 8    echo "usage: $0 file1 file2"

 9    echo "where both files must be .odt files"

10    exit $1

11 } >&2

12

13 # assure two readable arg filenames which end in .odt

14 if (( $# != 2 ))

15 then

16     usagexit 1

17 fi

18 if [[ $1 != *.odt || $2 != *.odt ]]

19 then

20     usagexit 2

21 fi

22 if [[ ! -r $1 || ! -r $2 ]]

23 then

24     usagexit 3

25 fi

26

27 BAS1=$(basename "$1" .odt)

28 BAS2=$(basename "$2" .odt)

29

30 # unzip them someplace private

31 PRIV1="/tmp/${BAS1}.$$_1"

32 PRIV2="/tmp/${BAS2}.$$_2"

33

34 # make absolute

35 HERE=$(pwd)

36 if [[ ${1:0:1} == '/' ]]

37 then

38     FULL1="${1}"

39 else

40     FULL1="${HERE}/${1}"

41 fi

42

43 # make absolute

44 if [[ ${2:0:1} == '/' ]]

45 then

46     FULL2="${2}"

47 else

48     FULL2="${HERE}/${2}"

49 fi

50

51 # mkdir scratch areas and check for failure

52 # N.B. must have whitespace around the { and } and

53 #      must have the trailing ; in the {} lists

54 mkdir "$PRIV1" || { echo Unable to mkdir $PRIV1 ; exit 4; }

55 mkdir "$PRIV2" || { echo Unable to mkdir $PRIV2 ; exit 5; }

56

57 cd "$PRIV1"

58 unzip -q "$FULL1"

59 sed -e 's/>/>\

60 /g' -e 's/</\

61 </g' content.xml > contentwnl.xml

62	

63 cd "$PRIV2"

64 unzip -q "$FULL2"

65 sed -e 's/>/>\

66 /g' -e 's/</\

67 </g' content.xml > contentwnl.xml

68

69 cd $HERE

70

71 diff "${PRIV1}/contentwnl.xml" "${PRIV2}/contentwnl.xml"

72

73 rm -rf $PRIV1 $PRIV2

	#!/usr/bin/env bash

	# cookbook filename: getopts_example

	#

	# using getopts

	#

	aflag=

	bflag=

	while getopts 'ab:' OPTION

	do

	  case $OPTION in

	  a)	aflag=1

			;;

	  b)	bflag=1

			bval="$OPTARG"

			;;

	  ?)	printf "Usage: %s: [-a] [-b value] args\n" $(basename $0) >&2

			exit 2

			;;

	  esac

	done

	shift $(($OPTIND - 1))



	if [ "$aflag" ]

	then

	  printf "Option -a specified\n"

	fi

	if [ "$bflag" ]

	then

	  printf 'Option -b "%s" specified\n' "$bval"

	fi

	printf "Remaining arguments are: %s\n" "$*"

	getopts 'ab:' OPTION

	#!/usr/bin/env bash

	# cookbook filename: getopts_custom

	#

	# using getopts - with custom error messages

	#

	aflag=

	bflag=

	# since we don't want getopts to generate error

	# messages, but want this script to issue its

	# own messages, we will put, in the option list, a

	# leading ':' v---here to silence getopts.

	while getopts :ab: FOUND

	do

		case $FOUND in

		a)	  aflag=1

			  ;;

		b)    bflag=1

			  bval="$OPTARG"

			  ;;

        \:)	  printf "argument missing from -%s option\n" $OPTARG

			  printf "Usage: %s: [-a] [-b value] args\n" $(basename $0)

			  exit 2

			  ;;

		\?)   printf "unknown option: -%s\n" $OPTARG

			  printf "Usage: %s: [-a] [-b value] args\n" $(basename $0)

			  exit 2

			  ;;

       esac >&2

    done

	shift $(($OPTIND - 1))



	if [ "$aflag" ]

	then

		printf "Option -a specified\n"

	fi

	if [ "$bflag" ]

	then

	    printf 'Option -b "%s" specified\n' "$bval"

	fi

	    printf "Remaining arguments are: %s\n" "$*"

	cat $1 | sed -e 's/>/>\

	/g' | grep '<a' | while IFS='"' read a b c ; do echo $b; done

	<a href="blah...blah...blah

	  other stuff >

	cat file | sed -e 's/>/>\

	/g'

	cat file | sed -e 's/>/>\

	/g' | grep '<a'

	cat file | sed -e 's/>/>\

	/g' | grep '".*"'

	#!/usr/bin/env bash

	# cookbook filename: parseViaArray

	#

	# find the file size

	# use an array to parse the ls -l output into words



	LSL=$(ls -ld $1)



	declare -a MYRA

	MYRA=($LSL)



	echo the file $1 is ${MYRA[4]} bytes.

	-rw-r--r--1 albing users 113 2006-10-10 23:33 mystuff.txt

	declare -a MYRA

	MYRA=(first second third home)

	declare -a MYRA

	MYRA=($(ls -ld $1))

	#!/usr/bin/env bash

	# cookbook filename: parseViaFunc

	#

	# parse ls -l via function call

	# an example of output from ls -l follows:

	# -rw-r--r--1 albing users 126 2006-10-10 22:50 fnsize



	function lsparts ()

	{

		PERMS=$1

		LCOUNT=$2

		OWNER=$3

		GROUP=$4

		SIZE=$5

		CRDATE=$6

		CRTIME=$7

		FILE=$8

	}

	lsparts $(ls -l "$1")



	echo $FILE has $LCOUNT 'link(s)' and is $SIZE bytes long.

	$ ./fnsize fnsize

	fnsize has 1 link(s) and is 311 bytes long.

	$

	#!/usr/bin/env bash

	# cookbook filename: parseViaRead

	#

	# parse ls -l with a read statement

	# an example of output from ls -l follows:

	# -rw-r--r--1 albing users 126 2006-10-10 22:50 fnsize

	ls -l "$1" | { read PERMS LCOUNT OWNER GROUP SIZE CRDATE CRTIME FILE ;

			       echo $FILE has $LCOUNT 'link(s)' and is $SIZE bytes long. ;

			     }

	read -a MYRAY

	#!/usr/bin/env bash

	# cookbook filename: pluralize

	#

	# A function to make words plural by adding an s

	# when the value ($2) is != 1 or -1

	# It only adds an 's'; it is not very smart.

	#

	function plural ()

	{

		if [ $2 -eq 1 -o $2 -eq -1 ]

		then

			echo ${1}

		else

			echo ${1}s

		fi

	}



	while read num name

	do

		echo $num $(plural "$name" $num)

	done

	$ cat input.file

	1 hen

	2 duck

	3 squawking goose

	4 limerick oyster

	5 corpulent porpoise



	$ ./pluralize < input.file

	1 hen

	2 ducks

	3 squawking gooses

	4 limerick oysters

	5 corpulent porpoises

	$

	if (( $2 == 1 || $2 == -1 ))

	#!/usr/bin/env bash

	# cookbook filename: onebyone

	#

	# parsing input one character at a time



	while read ALINE

	do

		for ((i=0; i < ${#ALINE}; i++))

		do

			ACHAR=${ALINE:i:1}

			# do something here, e.g. echo $ACHAR

		done

	done

	svn status src | grep '^\?' | cut -c8- | \

	while read fn; do echo "$fn"; rm -rf "$fn"; done

	#!/usr/bin/env bash

	# cookbook filename: dbiniter

	#

	# initialize databases from a standard file

	# creating databases as needed.



	DBLIST=$(mysql -e "SHOW DATABASES;" | tail +2)

	select DB in $DBLIST "new..."

	do



		if [[ $DB == "new..." ]]

		then



			printf "%b" "name for new db: "

			read DB rest

			echo creating new database $DB



        mysql -e "CREATE DATABASE IF NOT EXISTS $DB;"

	fi

	

	if [ "$DB" ]

	then

		echo Initializing database: $DB

		mysql $DB < ourInit.sql

	fi

	done

	# Here's an easy one, what users, home directories and shells do

	# we have on this NetBSD system

	$ cut -d':' -f1,6,7 /etc/passwd

	root:/root:/bin/csh

	toor:/root:/bin/sh

	daemon:/:/sbin/nologin

	operator:/usr/guest/operator:/sbin/nologin

	bin:/:/sbin/nologin

	games:/usr/games:/sbin/nologin

	postfix:/var/spool/postfix:/sbin/nologin

	named:/var/chroot/named:/sbin/nologin

	ntpd:/var/chroot/ntpd:/sbin/nologin

	sshd:/var/chroot/sshd:/sbin/nologin

	smmsp:/nonexistent:/sbin/nologin

	uucp:/var/spool/uucppublic:/usr/libexec/uucp/uucico

	nobody:/nonexistent:/sbin/nologin

	jp:/home/jp:/usr/pkg/bin/bash



	# What is the most popular shell on the system?

	$ cut -d':' -f7 /etc/passwd | sort | uniq -c | sort -rn

		10 /sbin/nologin

		2 /usr/pkg/bin/bash

		1 /bin/csh

		1 /bin/sh

		1 /usr/libexec/uucp/uucico



	# Now let's see the first two directory levels

	$ cut -d':' -f6 /etc/passwd | cut -d'/' -f1-3 | sort -u

	/

	/home/jp

	/nonexistent

	/root

	/usr/games

	/usr/guest

	/var/chroot

	/var/spool

	# Users, home directories and shells, but swap the last two

	# and use a tab delimiter

	$ awk 'BEGIN {FS=":"; OFS="\t"; } { print $1,$7,$6; }' /etc/passwd

	root → /bin/csh → /root

	toor → /bin/sh → /root

	daemon → /sbin/nologin → /

	operator → /sbin/nologin → /usr/guest/operator

	bin → /sbin/nologin → /

	games → /sbin/nologin → /usr/games

	postfix → /sbin/nologin → /var/spool/postfix

	named → /sbin/nologin → /var/chroot/named

	ntpd → /sbin/nologin → /var/chroot/ntpd

	sshd → /sbin/nologin → /var/chroot/sshd

	smmsp → /sbin/nologin → /nonexistent

	uucp → /usr/libexec/uucp/uucico → /var/spool/uucppublic

	nobody → /sbin/nologin → /nonexistent

	jp → /usr/pkg/bin/bash → /home/jp



	# Multiples of whitespace and swapped, first field removed

	$ grep '^# [1-9]' /etc/hosts | awk '{print $3,$2}'

	10.255.255.255 10.0.0.0

	172.31.255.255 172.16.0.0

	192.168.255.255 192.168.0.0

	$ grep csh /etc/passwd

	root:*:0:0:Charlie &:/root:/bin/csh



	$ sed 's/csh$/sh/' /etc/passwd | grep '^root'

	root:*:0:0:Charlie &:/root:/bin/sh

	$ cat data_file

	Line 1 ends

	Line 2 ends

	Line 3 ends

	Line 4 ends

	Line 5 ends





	$ awk '{print $1, $2+5, $3}' data_file

	Line 6 ends

	Line 7 ends

	Line 8 ends

	Line 9 ends

	Line 10 ends





	# If the second field contains '3', change it to '8' and mark it

	$ awk '{ if ($2 == "3") print $1, $2+5, $3, "Tweaked" ; else print $0; }' data_file

	Line 1 ends

	Line 2 ends

	Line 8 ends Tweaked

	Line 4 ends

	Line 5 ends

	# Show the whitespace in our sample file

	$ while read; do echo ~~"$REPLY"~~; done < whitespace

	~~ This line has leading spaces.~~

	~~This line has trailing spaces. ~~

	~~ This line has both leading and trailing spaces. ~~

	~~ → Leading tab.~~

	~~Trailing tab. → ~~

	~~ → Leading and trailing tab. → ~~

	~~ → Leading mixed whitespace.~~

	~~Trailing mixed whitespace. →     ~~

	~~ → Leading and trailing mixed whitespace. →     ~~

	$ while read REPLY; do echo ~~"$REPLY"~~; done < whitespace

	~~This line has leading spaces.~~

	~~This line has trailing spaces.~~

	~~This line has both leading and trailing spaces.~~

	~~Leading tab.~~

	~~Trailing tab.~~

	~~Leading and trailing tab.~~

	~~Leading mixed whitespace.~~

	~~Trailing mixed whitespace.~~

	~~Leading and trailing mixed whitespace.~~

	# Leading spaces only

	$ while read; do echo "~~${REPLY## }~~"; done < whitespace

	~~This line has leading spaces.~~

	~~This line has trailing spaces. ~~

	~~This line has both leading and trailing spaces. ~~

	~~ → Leading tab.~~

	~~Trailing tab. ~~

	~~ → Leading and trailing tab. → ~~

	~~ → Leading mixed whitespace.~~

	~~Trailing mixed whitespace. →     ~~

	~~ → Leading and trailing mixed whitespace. →     ~~



	# Trailing spaces only

	$ while read; do echo "~~${REPLY%% }~~"; done < whitespace

	~~ This line has leading spaces.~~

	~~This line has trailing spaces.~~

	~~ This line has both leading and trailing spaces.~~

	~~ → Leading tab.~~

	~~Trailing tab. ~~

	~~ → Leading and trailing tab. → ~~

	~~     → Leading mixed whitespace.~~

	~~Trailing mixed whitespace. →     ~~

	~~     → Leading and trailing mixed whitespace. →     ~~

	$ cat data_file

	Header1             Header2              Header3

	Rec1_Field1         Rec1_Field2          Rec1_Field3

	Rec2_Field1         Rec2_Field2          Rec2_Field3

	Rec3_Field1         Rec3_Field2          Rec3_Field3



	$ cat data_file | tr -s ' ' '\t'

	Header1 → Header2 → Header3

	Rec1_Field1 → Rec1_Field2 → Rec1_Field3

	Rec2_Field1 → Rec2_Field2 → Rec2_Field3

	Rec3_Field1 → Rec3_Field2 → Rec3_Field3

	$ cat data_file1

	Header1             Header2              Header3

	Rec1 Field1         Rec1 Field2          Rec1 Field3

	Rec2 Field1         Rec2 Field2          Rec2 Field3

	Rec3 Field1         Rec3 Field2          Rec3 Field

	$ cat fixed-length_file

	Header1-----------Header2-------------------------Header3---------

	Rec1 Field1       Rec1 Field2                     Rec1 Field3

	Rec2 Field1       Rec2 Field2                     Rec2 Field3

	Rec3 Field1       Rec3 Field2                     Rec3 Field3

$ gawk ' BEGIN { FIELDWIDTHS = "18 32 16"; OFS = "\t" } { $1 = $1; gsub(/ +\t/, "\

	t"); gsub(/ +$/, ""); print }' fixed-length_file

	Header1----------- → Header2------------------------- → Header3---------

	Rec1 Field1 → Rec1 Field2 → Rec1 Field3

	Rec2 Field1 → Rec2 Field2 → Rec2 Field3

	Rec3 Field1 → Rec3 Field2 → Rec3 Field3



	$ gawk ' BEGIN { FIELDWIDTHS = "18 32 16"; OFS = "\t" } { $1 = $1; gsub(/ +\t/, "\

	t"); gsub(/ +$/, ""); print }' fixed-length_file | hexdump -C

	00000000 48 65 61 64 65 72 31 2d 2d 2d 2d 2d 2d 2d 2d 2d |Header1---------|

	00000010 2d 2d 09 48 65 61 64 65 72 32 2d 2d 2d 2d 2d 2d |--.Header2------|

	00000020 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|

	00000030 2d 2d 2d 09 48 65 61 64 65 72 33 2d 2d 2d 2d 2d |---.Header3-----|

	00000040 2d 2d 2d 2d 0a 52 65 63 31 20 46 69 65 6c 64 31 |----.Rec1 Field1|

	00000050 09 52 65 63 31 20 46 69 65 6c 64 32 09 52 65 63 |.Rec1 Field2.Rec|

	00000060 31 20 46 69 65 6c 64 33 0a 52 65 63 32 20 46 69 |1 Field3.Rec2 Fi|

	00000070 65 6c 64 31 09 52 65 63 32 20 46 69 65 6c 64 32 |eld1.Rec2 Field2|

	00000080 09 52 65 63 32 20 46 69 65 6c 64 33 0a 52 65 63 |.Rec2 Field3.Rec|

	00000090 33 20 46 69 65 6c 64 31 09 52 65 63 33 20 46 69 |3 Field1.Rec3 Fi|

	000000a0 65 6c 64 32 09 52 65 63 33 20 46 69 65 6c 64 33 |eld2.Rec3 Field3|

	000000b0 0a                                              |.|

	000000b1

	$ wc -l content.xml

			1 content.xml

	

	$ sed -e 's/>/>\

	/g' content.xml | wc -l

		1687

	$ cat fixed-length

	Line_1_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_2_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_3_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_4_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_5_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_6_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_7_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_8_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_9_ _

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_10_

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_11_

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZLine_12_

	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ





	$ wc -l fixed-length

		  1 fixed-length



	$ sed 's/.\{48\}/&\

	/g;' fixed-length

	Line_1_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_2_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_3_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_4_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_5_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_6_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_7_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_8_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_9_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_10_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_11_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_12_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ





	$ perl -pe 's/(.{48})/$1\n/g;' fixed-length

	Line_1_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_2_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_3_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_4_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_5_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_6_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_7_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_8_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_9_ _aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_10_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_11_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	Line_12_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaZZZ

	$ awk 'BEGIN { FS="\t"; OFS="\",\"" } { gsub(/"/, "\"\""); $1 = $1; printf "\"%s\"\

	n", $0}' tab_delimited

	"Line 1","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 2","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 3","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 4","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	$ perl -naF'\t' -e 'chomp @F; s/"/""/g for @F; print q(").join(q(","), @F).qq("\n);'

	tab_delimited

	"Line 1","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 2","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 3","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	"Line 4","Field 2","Field 3","Field 4","Field 5 with ""internal"" double-quotes"

	#!/bin/bash -

	# Set a sane/secure path

	PATH='/usr/local/bin:/bin:/usr/bin'

	# It's almost certainly already marked for export, but make sure

	export PATH

	export PATH=$(getconf PATH)

	export PATH='/usr/local/bin:/bin:/usr/bin'

	#!/usr/bin/env bash

	# cookbook filename: finding_tools

	

	# export may or may not also be needed, depending on what you are doing

	

	# These are fairly safe bets

	_cp='/bin/cp'

	_mv='/bin/mv'

	_rm='/bin/rm'



	# These are a little trickier

	case $(/bin/uname) in

	    'Linux')

	        _cut='/bin/cut'

	        _nice='/bin/nice'

	        # [...]

	    ;;

	    'SunOS')

	        _cut='/usr/bin/cut'

	        _nice='/usr/bin/nice'

	        # [...]

	    ;;

	    # [...]

	esac

	$ alias unalias=echo

	$ alias builtin=ls



	$ builtin unalias vi

	ls: unalias: No such file or directory

	ls: vi: No such file or directory



	$ unalias -a

	-a

	ulimit -H -c 0 --

	# Set a sane/secure IFS (note this is bash & ksh93 syntax only--not portable!)

	IFS=$' \t\n'

	1 IFS=' • → ¶

	2 '

	1 IFS='• ¶

	2 • → '

	# Set a sane/secure umask variable and use it

	# Note this does not affect files already redirected on the command line

	# 002 results in 0774 perms, 077 results in 0700 perms, etc...

	UMASK=002

	umask $UMASK

	umask 002

	# Run a new shell so you don't affect your current

	environment

	/tmp$ bash



	# Check the current settings

	/tmp$ touch um_current



	# Check some other settings

	/tmp$ umask 000 ; touch um_000

	/tmp$ umask 022 ; touch um_022

	/tmp$ umask 077 ; touch um_077



	/tmp$ ls -l um_*

	-rw-rw-rw-     1 jp        jp       0 Jul 22 06:05 um000

	-rw-r--r--     1 jp        jp       0 Jul 22 06:05 um022

	-rw-------     1 jp        jp       0 Jul 22 06:05 um077

	-rw-rw-r--     1 jp        jp       0 Jul 22 06:05 umcurrent



	# Clean up and exit the sub-shell

	/tmp$ rm um_*

	/tmp$ exit

	#!/usr/bin/env bash

	# cookbook filename: chkpath.1

	# Check your $PATH for world-writable or missing directories



	exit_code=0



	for dir in ${PATH//:/ }; do

	    [ -L "$dir" ] && printf "%b" "symlink, "

	    if [ ! -d "$dir" ]; then

	        printf "%b" "missing\t\t"

	          (( exit_code++ ))

	    elif [ "$(ls -lLd $dir | grep '^d.......w. ')" ]; then

	          printf "%b" "world writable\t"

	          (( exit_code++ ))

	    else

	          printf "%b" "ok\t\t"

	    fi

	    printf "%b" "$dir\n"

	done

	exit $exit_code

	# ./chkpath

	ok              /usr/local/sbin

	ok              /usr/local/bin

	ok              /sbinok /bin

	ok              /usr/sbin

	ok              /usr/bin

	ok              /usr/X11R6/bin

	ok              /root/bin

	missing         /does_not_exist

	world writable  /tmp

	symlink, world writable /tmp/bin

	symlink, ok /root/sbin

	# Make sure $TMP is set to something

	[ -n "$TMP" ] || TMP='/tmp'



	# Make a "good enough" random temp directory

	until [ -n "$temp_dir" -a ! -d "$temp_dir" ]; do

	    temp_dir="/tmp/meaningful_prefix.${RANDOM}${RANDOM}${RANDOM}"

	done

	mkdir -p -m 0700 $temp_dir

	  || { echo "FATAL: Failed to create temp dir '$temp_dir': $?"; exit 100 }

	  # Make a "good enough" random temp file

	  until [ -n "$temp_file" -a ! -e "$temp_file" ]; do

	      temp_file="/tmp/meaningful_prefix.${RANDOM}${RANDOM}${RANDOM}"

	done

	touch $temp_file && chmod 0600 $temp_file

	  || { echo "FATAL: Failed to create temp file '$temp_file': $?"; exit 101 }

	# cookbook filename: make_temp



	# Make a "good enough" random temp directory

	until [ -n "$temp_dir" -a ! -d "$temp_dir" ]; do

	    temp_dir="/tmp/meaningful_prefix.${RANDOM}${RANDOM}${RANDOM}"

	done

	mkdir -p -m 0700 $temp_dir \

	  || { echo "FATAL: Failed to create temp dir '$temp_dir': $?"; exit 100 }



	# Make a "good enough" random temp file in the temp dir

	temp_file="$temp_dir/meaningful_prefix.${RANDOM}${RANDOM}${RANDOM}"

	touch $temp_file && chmod 0600 $temp_file \

	  || { echo "FATAL: Failed to create temp file '$temp_file': $?"; exit 101 }

	# cookbook filename: clean_temp



	# Do our best to clean up temp files no matter what

	# Note $temp_dir must be set before this, and must not change!

	cleanup="rm -rf $temp_dir"

	trap "$cleanup" ABRT EXIT HUP INT QUIT