Bash-Beginners-Guide

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Bash Guide for Beginners rm "$TEMP" michel ~/testdir> sysnotes.sh Output will be saved in /var/tmp/sysconfig.out. Saving root account info... Enter comment or [ENTER] for no comment: hint for password: blue lagoon Saving hosts information... Enter comment or [ENTER] for no comment: in central DNS michel ~/testdir> cat /var/tmp/sysconfig.out Your root account info: root:x:0:0:root:/root:/bin/bash hint for password: blue lagoon Your local host configuration: 127.0.0.1 localhost.localdomain localhost 192.168.42.1 tintagel.kingarthur.com tintagel in central DNS 8.2.4.3. Closing file descriptors Since child processes inherit open file descriptors, it is good practice to close a file descriptor when it is no longer needed. This is done using the exec fd cat listdirs.sh #!/bin/bash # This script prints standard output unchanged, while standard error is # redirected for processing by awk. INPUTDIR="$1" # fd 6 targets fd 1 target (console out) in current shell exec 6>&1 # fd 1 targets pipe, fd 2 targets fd 1 target (pipe), # fd 1 targets fd 6 target (console out), fd 6 closed, execute ls ls "$INPUTDIR"/* 2>&1 >&6 6>&- \ # Closes fd 6 for awk, but not for ls. | awk 'BEGIN { FS=":" } { print "YOU HAVE NO ACCESS TO" $2 }' 6>&- # fd 6 closed for current shell exec 6>&- 8.2.4.4. Here documents Frequently, your script might call on another program or script that requires input. The here document provides a way of instructing the shell to read input from the current source until a line containing only the search string is found (no trailing blanks). All of the lines read up to that point are then used as the standard input for a command. Chapter 8. Writing interactive scripts 104
Bash Guide for Beginners The result is that you don't need to call on separate files; you can use shell-special characters, and it looks nicer than a bunch of echo's: michel ~> cat startsurf.sh #!/bin/bash # This script provides an easy way for users to choose between browsers. echo "These are the web browsers on this system:" # Start here document cat startsurf.sh These are the web browsers on this system: mozilla links lynx konqueror opera netscape Which is your favorite? opera Starting opera, please wait... Although we talk about a here document, it is supposed to be a construct within the same script. This is an example that installs a package automatically, eventhough you should normally confirm: #!/bin/bash # This script installs packages automatically, using yum. if [ $# -lt 1 ]; then echo "Usage: $0 package." exit 1 fi yum install $1
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Bash Guide for Beginners Machtelt G
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Bash Guide for Beginners Table of C
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Bash Guide for Beginners Table of C
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Table of Contents Glossary C.......
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Introduction 1. Why this guide? The
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Revision 1.6 2005-03-01 Revised by:
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Bash Guide for Beginners See Chapte
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Bash Guide for Beginners mia:~> cat
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Bash Guide for Beginners When invok
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More information about the file des
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Built-in commands are necessary to
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• Brace expansion • Tilde expan
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A number of methods can be used; on
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Bash Guide for Beginners stop in ea
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Chapter 2. Writing and debugging sc
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the documentation of your favorite
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Bash Guide for Beginners Comments a
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Bash Guide for Beginners + set +x I
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Chapter 3. The Bash environment In
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Bash Guide for Beginners local pid
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MOZILLA_FIVE_HOME=/usr/lib/mozilla
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Bash Guide for Beginners franky ~>
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the GNU Awk programming language is
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Bash Guide for Beginners 3.2.4. Res
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LINES MACHTYPE MAILCHECK OLDPWD OPT
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two is the second positional parame
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Bash Guide for Beginners 3.3.1. Why
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A correctly-formed brace expansion
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Bash Guide for Beginners If the sub
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of the whitespace characters "space
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Page 65 and 66: Two regular expressions may be conc
Page 67 and 68: LABEL=/ / ext3 defaults 1 1 If this
Page 69 and 70: cathy ~> ls -ld [[:digit:]]* drwxrw
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Page 73 and 74: sandy ~> sed -n '/a text/,/This/p'
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Page 93 and 94: [root@elegance root]# We switch to
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Page 101 and 102: Upon successful condition testing,
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Page 105 and 106: 8.2. Catching user input 8.2.1. Usi
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Page 119 and 120: touch pic-`date +%s`.jpg sleep 300
Page 121 and 122: DISKFUL=$(df -h $WEBDIR | grep -v F
Page 123 and 124: ;; 2) $FORTUNE startrek ;; 3) $FORT
Page 125 and 126: [carol@octarine ~/test] ls -a ./ ..
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Page 133 and 134: if [ -z $1 ]; then echo "Usage: $0
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Page 143 and 144: zip2 "$TAR" echo "...done." >> "$LO
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Page 149 and 150: Bash Guide for Beginners 2. Write a
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Page 153 and 154: if [ $i -eq 5 ] ArrowUp+Enter or !!
Page 155 and 156: cd Change directory. cdp/cdplay An
Page 157 and 158: Bash Guide for Beginners gimp grep
Page 159 and 160: Send and receive mail. man Read man
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W Bash Guide for Beginners w Show w
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Index A aliases Section 3.5.1 ANSI-
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Bash Guide for Beginners Section 3.
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J Bash Guide for Beginners K kill k
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eadonly Section 10.1.3 regular expr
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Bash Guide for Beginners vi(m) Sect
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