This & That Refer to 'that last thing', and 'the first thing': 1fortune -l > file1 2cat !$ | tr -d u > file2 3cat file1 !$ 4diff !^ !$ NB: this can go wrong: 1ls -l file1 file2 2cat !^ NB: this only works when running bash interactively, never in scripts. Lists You can put a list inside any bash argument, and bash will …

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Number checks are too long. 1if [ "$x" -gt "$y" ]; then 2 echo "$x" 3else 4 echo "$y" 5fi Write a shorter number check like this: echo $(( x > y ? x : y )) Longer checks are possible: 1col(){ 2 n=$(( $1 % 2 == 0 ? $1 /2 : $1 * 3 + 1 )) 3 echo $n 4 [ $n -eq 1 ] || col $n 5} 6 7col 4 8col 5 9col 9 10col 27

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Requirements Making Scripts Place this in a file called options.sh, and make it executable. 1#!/bin/sh 2 3echo "This script is called $0" 4 5while getopts oe: choice ; do 6 case "$choice" in 7 o) 8 echo "This is option number '${OPTIND}'." 9 ;; 10 e) echo "Option number '${OPTIND}' uses this variable: '${OPTARG}'." 11 …

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Make a script for your regular shell commands. 1name=look 2echo '#!/bin/sh > ${name}.sh 3echo 'echo "This script is called $0"' 4chmod u+x !$ 5./!$ Notice the single-quotes, not double quotes.

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The output from tree is too long. Turn on colours and read with less: 1tree -C | less -R j: scroll down k: scroll up g: go-to top G: go-to bottom q: quit Search with less /<word> to search <Escape>u to undo search highlights Make search case insensitive with less -i. 1less -i README.md The man pages often use less. …

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Run commands in background 1ls -Rilt ~ & 2jobs 3find ~/.cache/ -type d -exec du '{}' -h ';' | sort -h & 4jobs Stop background command having output 1disown The command will continue as it was. You can see it with top.

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Remove long lines from bash history 1sed -i -r '/([^ ]{100,})\s?$/d' $HISTFILE Convert a csv file to markdown 1column -o '|' -ts, "$1" + | sed -r '0,/./p ; 0,/./s/[a-zA-Z ]/-/g; 0,/^|/s/|-/|:/g' Change a CSV header 1from=number 2to=quantity 3sed -i "1 s///" "".csv Replace first instance of word 1sed …

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Done <C-d> If you have a command, Control + d will execute the command. If you have nothing, exit. Search & Clear Highlights You can search in many programs by using /. Most programs let you clear the highlighting with <Esc>+u. Track Live Changes Follow a file as new lines are added to it: 1tail -f "${file}" Watch …

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Vi-Commands Copy, move, and delete with vi-keys. 1echo 'set editing-mode vi' >> ~/.inputrc 2echo 'set keymap vi-insert' >> ~/.inputrc 3exec bash Try ls <C-n> and ls <C-p> Use python in vi-mode 1echo 'export PYTHON_BASIC_REPL=true' >> ~/.bashrc 2exec bash Alias Expansion 1echo '"\C- ": shell-expand-line' >> ~/.inputrc …

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