Reference

Last updated on 2025-09-17 | Edit this page

Shell Cheat Sheet

Shell: Basics

pwd - print working directory

man - display the user manual

history - display the history list with line numbers, use n to limit the list

ls - list contents of a directory

  • ls -l - list file information
  • ls -lh - list human readable file information
  • ls -F - list files and directories (directories will have a trailing /)
  • ls -a - list all files, including hidden files
  • ls *.txt - list all files that end with .txt

cd - change directory

  • cd pathname - take you to the directory specified by pathname
  • cd ~ - take you to your home directory
  • cd .. - take you up one directory

Shell: Interacting with Files

mkdir - make a directory

cat - print to shell or send file or files to output

head - output first 10 lines of a file or files

tail - output last 10 lines of a file or files

mv - rename or move a file or files. Syntax for renaming a file: mv FILENAME NEWFILENAME

cp - make a backup copy of a file or files. Syntax: cp FILENAME NEWFILENAME

> - redirect output. Syntax with cat: cat FILENAME1 FILENAME2 > NEWFILENAME

>> - redirect output by appending to the filename specified. Syntax with cat: cat FILENAME1 FILENAME2 >> NEWFILENAME

rm - remove a file or files. NB: USE WITH EXTREME CAUTION!!!

  • rm -ri - delete a directory, even if it is not empty, but will ask you to confirm each deletion

rmdir -r - delete a directory, even if it is not empty

touch - update timestamp information on files, or create a file or files if they don’t exist

Shell: Wildcards

? - a placeholder for one character or number

* - a placeholder for zero or more characters or numbers

[] - define a class of characters

Examples

  • foobar? - match 7-character strings starting with foobar and ending with one character or number
  • foobar* - match strings that start with foobar and end with zero or more other characters or numbers
  • foobar*txt - match strings that start with foobar and end with txt
  • [1-9]foobar? - match 8-character strings that start that start with a number, have foobar after the number, and end with any character or number

Shell: Counting and Mining

wc - word count

  • wc -w - count words
  • wc -l - count lines
  • wc -c - count characters

sort - sort input (alphabetic sorting)

  • sort -n - sort input numerically

grep - global regular expression print

  • grep -c - display counts of matches for each file
  • grep -i - match with case insensitivity
  • grep -w - match whole words
  • grep -v - exclude match
  • grep --file=FILENAME.txt - use the file FILENAME.txt as the source of strings used in query

| - (vertical bar character) send output from one command into another command. Example: wc -l *.txt | sort -n

Shell: Working with Free Text

sed - is used to modify files - sed -e - run multiple commands

tr - translates or deletes characters in a file. Some allowed sequences:

  • [:punct:] - punctuation characters
  • [:upper:] - upper-case characters
  • [:lower:] - lower-case alphabetic characters

Example: tr '''\n - translate every blank space into \n, then renders on a new line

uniq - report or filters repeated lines in a file - uniq -c- do a word count of the duplicates