Unix tool tip

'The enjoyment of one's tools is an essential ingredient of successful work.' -- Donald E. Knuth

Emacs search, ignoring punctuation or spaces between words: M-s w

Awk FAQ faqs.org/faqs/computer-…

In Emacs, you can delete all but one space with M-x just-one-space. Typically bound to M-SPC (Alt-Space).

sed script to delete last line of a file: $d

List files in descending order of size: ls -S

Doing SQL-like joins on CSV files at the command line johndcook.com/blog/2019/12/3…

sed debugger: aurelio.net/sedsed/

Show which lines are repeated in a sorted file: uniq -d

'It is easier to port a shell than a shell script.' -- Larry Wall

sed pattern for lines not containing spam: /spam/!

Awk to Perl translator: metacpan.org/pod/App::a2p

Replace all instances of a word in a shell command johndcook.com/blog/2022/10/2…

Show how many times each line in a sorted file is repeated: uniq -c

The sed command p prints. For example, print lines 3 through 7 of a file: sed -n '3,7p' somefile

Unified config files johndcook.com/blog/2026/05/0…

"I run my company from Emacs" thetypicalset.com/blog/emacs-as-…

Sort a file in case-insensitive order: sort -f. 'f' for 'fold,' i.e. fold upper and lower case together

Kill a line in Emacs from anywhere on that line: M-shift-backspace

Output a file, displaying non-printing characters: cat -v

In vim, ^ takes you to the first non-blank character of a line. In sed, ^ refers to the first line of a file. In regex, ^ matches the beginning of a string.

Similarly, in bash !^ refers to the first argument to the previous command. This makes sense because ! refers to commands and ^ often refers to the beginning of something.

In bash !$ refers to the last argument to the previous command. Example usage: copying a file to a directory and then cd'ing into that directory cp some_file.txt big/long/complicated/path/to/directory cd !$