Replace a regexp pattern in many files at once 

vi +'bufdo %s/pattern/replacement/g | update' +q $(grep -rl pattern /path/to/dir)

September 15, 2011 — bashoneliners

Explanation

  • The inner grep will search recursively in specified directory and print the filenames that contain the pattern.
  • All files will be opened in vi, one buffer per file.
  • The arguments starting with + will be executed as vi commands:
    • bufdo %s/pattern/replacement/g | update = perform the pattern substitution in all files and save the changes
    • q = exit vi

Limitations

The :bufdo command might not be there in old versions of vim.

text-processing file-manipulation
grep vi