presentation.md

Stupid Unix Tricks

Real Basics

Keyboard Shortcuts

• Arrow keys do what you'd expect
• ctrl + a will put you at the beginning of the line
• ctrl + e will put you at the end
• ctrl + w deletes previous word (space delimited)
• tab will auto-complete commands (requires bash-completion)
• ctrl + l forces a screen redraw
• ctrl + r recursively searches through history
• ctrl + c stops

Helpful Bashisms

• !! - substitute in last command here
• !$ - place last argument of last command here
• ./ - current directory
• cd - change to home directory
• cd - - Change to last directory
• ^foo^bar - Run last command replacing string foo with bar
• fc - Open last command in $EDITOR. Execute upon save+quit
• ctrl+x; e - Open current command line in $EDITOR

Helpful Things

Pipe Viewer

Replacement for cat that shows file progress via stderr

pigz

Parallel gz. Compression sizes are similar if not same, but uses multiple cores

pigz -c ./ChessData.tar > ChessData.tar.pigz.gz

Same input Multiple outputs

You can send the same input to multiple outputs without having to run multiple commands

pv ./ChessData.tar | tee >(gzip - > /tmp/ChessData.tar.gz) >(bzip2 - > /tmp/ChessData.tar.bz2) | xz - > /tmp/ChessData.tar.xz

flock

Use flock to make a lock with a file. This helps with cron jobs

* * * * * /usr/bin/flock -w 0 /path/to/cron.lock /usr/bin/php /path/to/cron.php

Clipboard access in CLI

Put a file into the clipboard

cat file.txt | xclip -selection clipboard -in

Put clipboard into file

xclip -selection clipboard -out > file.txt

Links

Command Line Tools Can Be 235x Faster Than Your Hadoop Cluster