How to pipe list of files returned by find command to cat to view all the files

Modern version

POSIX 2008 added the + marker to find which means it now automatically groups as many files as are reasonable into a single command execution, very much like xargs does, but with a number of advantages:

  1. You don't have to worry about odd characters in the file names.
  2. You don't have to worry about the command being invoked with zero file names.

The file name issue is a problem with xargs without the -0 option, and the 'run even with zero file names' issue is a problem with or without the -0 option — but GNU xargs has the -r or --no-run-if-empty option to prevent that happening. Also, this notation cuts down on the number of processes, not that you're likely to measure the difference in performance. Hence, you could sensibly write:

find . -exec grep something {} +

Classic version

find . -print | xargs grep something

If you're on Linux or have the GNU find and xargs commands, then use -print0 with find and -0 with xargs to handle file names containing spaces and other odd-ball characters.

find . -print0 | xargs -0 grep something

Tweaking the results from grep

If you don't want the file names (just the text) then add an appropriate option to grep (usually -h to suppressing 'headings'). To absolutely guarantee the file name is printed by grep (even if only one file is found, or the last invocation of grep is only given 1 file name), then add /dev/null to the xargs command line, so that there will always be at least two file names.


  1. Piping to another process (Although this WON'T accomplish what you said you are trying to do):

    command1 | command2

    This will send the output of command1 as the input of command2

  2. -exec on a find (this will do what you are wanting to do -- but is specific to find)

    find . -name '*.foo' -exec cat {} \;

    (Everything between find and -exec are the find predicates you were already using. {} will substitute the particular file you found into the command (cat {} in this case); the \; is to end the -exec command.)

  3. send output of one process as command line arguments to another process

    command2 `command1`

    for example:

    cat `find . -name '*.foo' -print`

    (Note these are BACK-QUOTES not regular quotes (under the tilde ~ on my keyboard).) This will send the output of command1 into command2 as command line arguments. Note that file names containing spaces (newlines, etc) will be broken into separate arguments, though.

Tags:

Unix

Pipe

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