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https://github.com/chubin/cheat.sheets
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58 lines
1.3 KiB
Plaintext
58 lines
1.3 KiB
Plaintext
# To implement a for loop:
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for file in *;
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do
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echo $file found;
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done
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# To implement a case command:
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case "$1"
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in
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0) echo "zero found";;
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1) echo "one found";;
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2) echo "two found";;
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3*) echo "something beginning with 3 found";;
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esac
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# Turn on debugging:
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set -x
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# Turn off debugging:
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set +x
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# Retrieve N-th piped command exit status
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printf 'foo' | grep -F 'foo' | sed 's/foo/bar/'
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echo ${PIPESTATUS[0]} # replace 0 with N
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# Lock file:
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( set -o noclobber; echo > my.lock ) || echo 'Failed to create lock file'
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# Fork bomb
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:(){ :|:& };:
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# Unix Roulette
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# (Courtesy of Bigown's answer in the joke thread)
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# DANGER! Don't execute!
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[ $[ $RANDOM % 6 ] == 0 ] && rm -rf /* || echo Click #Roulette
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# for loop in one line
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for i in $(seq 1 4); do echo $i; done
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# Check to see if a variable equals a specified integer
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if [ "$var" -eq "0" ]; then
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echo "var equals zero";
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fi
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# Test if a program exists in the path
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# There are false positives: aliases and functions
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command -v ${program} >/dev/null 2>&1 || error "${program} not installed"
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# Redirection
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# Please note that 2>&1 goes after
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my_command > command-stdout-stderr.txt 2>&1
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my_command > /dev/null 2>&1
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# Redirect stdout and stderr of cmd1 to cmd2
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cmd1 |& cmd2
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# Convert spaces to underscores in filenames
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for name in *\ *; do mv -vn "$name" "${name// /_}"; done
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