G.1. Standard Command-Line Options (Revision #3)

Over time, there has evolved a loose standard for the meanings of command-line option flags. The GNU utilities conform more closely to this "standard" than older UNIX utilities.

Traditionally, UNIX command-line options consist of a dash, followed by one or more lowercase letters. The GNU utilities added a double-dash, followed by a complete word or compound word.

The two most widely-accepted options are:

• -h
  
  --help
  
  Help: Give usage message and exit.
   
•  -v
  
  --version
  
  Version: Show program version and exit.

Other common options are:

•  -a
  
  --all
  
  All: show all information or operate on all arguments.
   
• -l
  
  --list
  
  List: list files or arguments without taking other action.
   
• -o
  
  Output filename
   
• -q
  
  --quiet
  
  Quiet: suppress stdout.
   
•  -r
  
  -R
  
  --recursive
  
  Recursive: Operate recursively (down directory tree).
   
• -v
  
  --verbose
  
  Verbose: output additional information to stdout or stderr.
   
• -z
  
  --compress
  
  Compress: apply compression (usually gzip).

However:

• In tar and gawk:
  
  -f
  
  --file
  
  File: filename follows.
   
• In cp, mv, rm:
  
  -f
  
  --force
  
  Force: force overwrite of target file(s).

  Many UNIX and Linux utilities deviate from this "standard," so it is dangerous to assume that a given option will behave in a standard way. Always check the man page for the command in question when in doubt.

A complete table of recommended options for the GNU utilities is available at the GNU standards page.