bash/globbing

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The following notes may apply to other shell environments besides bash, but have only been tested with bash.

Commands invoked via bash always, by default, have each of their arguments parsed via the glob system facility before being passed to the command.

Problem

This actively interferes with the ability of programs such as grep to behave intuitively when given a file-mask spec as input for processing, because:

  • any mask entered will apply only to the current folder.
  • folders are only included if their names also match the mask
    • ...thus not being useful as far as being the next layer of folders to search; the program will have to get its own directory listing for that.

Workarounds

Globbing can be turned off on a per-session basis:

  • set -o noglob
    turns off globbing
    put it in ~/.bashrc to make it the default
  • set +o noglob
    turns globbing back on
  • help set
    returns more information about bash's set command (the "set" manpage is for something else)

The user can bypass globbing (and other special-character processing) by enclosing the file-mask in quotes (single or double). bash will strip off the quotes but not parse the contents.

Links