Tip 109: Customize the grep Program

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Vim's Default grep Settings

• 'grepprg' setting specifies what to run in the shell when Vim's :grep command is executed.

References:

# If you open the file in vim,
# then you can \"ayy@a the next line to execute the vim command: 
:h 'grepprg'

• 'grepformat' setting tells Vim how to parse the output returned by the :grep command.

References:

# If you open the file in vim,
# then you can \"ayy@a the next line to execute the vim command: 
:h 'grepformat'

• Default settings on Unix systems:

  grepprg="grep -n $* /dev/null"
  grepformat="%f:%l:%m,%f:%l%m,%f %l%m"
  

  • The $* symbol used in the 'grepprg' setting is a placeholder, which is replaced with any arguments supplied to the :grep command.
  • The special tokens used in the 'grepformat' string are the same as those used by 'errorformat'.

    # If you open the file in vim,
    # then you can \"ayy@a the next line to execute the vim command: 
    :h errorformat
    

    • %f matches the filename
    • %l matches the line number
    • %m matches the text on that line

Make :grep Call ack

:set grepprg=ack\ --nogroup\ $*

Make ack Jump to Line and Column

• %c matches the column number

  :set grepprg=ack\ --nogroup\ --column\ $*
  :set grepformat=%f:%l:%c:%m
  

Alternative grep Plugins

• grep uses POSIX regular expressions, whereas ack uses Perl regular expressions.
• ack.vim and fugitive.vim create custom commands rather than overriding the :grep command, they can all coexist without conflict.