CODEWITHSUNDEEP
bashfunction
xralf
xralf

Reputation: 3632

Pipe commands in bash function

When you define a bash function you can call bash commands with command command.

function ls() {
  clear
  command ls "$@"
}

How would you pipe commands in bash function?

e.g.

function ls() {
  clear
  command ls "$@" | head
}

EDIT: The output would be OK, but there is --color=auto. Look here

Upvotes: 0

Views: 1948

Answers (2)

jeff
jeff

Reputation: 11

You can pipe the colour information generated by the ls command to head if you run ls in a so-called pseudo terminal (so that ls thinks it is writing its output to a terminal, and not a pipe). This can be achieved by using the script command.

ls() {
   type -P command 1>/dev/null || 
        { echo 'No "command" executable found!'; return 1; }
   clear
   script -q /dev/null command ls -G "$@" | tr -d '\r' | head
 }


 cat /usr/bin/command   # on Mac OS X 10.6.8
 #!/bin/sh
 # $FreeBSD: src/usr.bin/alias/generic.sh,v 1.2 2005/10/24 22:32:19 cperciva Exp $
 # This file is in the public domain.
 builtin `echo ${0##*/} | tr \[:upper:] \[:lower:]` ${1+"$@"}

For more information see: ls command operating differently depending on recipient

Upvotes: 1

Lewis Norton
Lewis Norton

Reputation: 7151

Try this in your ~/.bashrc

function ls() { clear ; builtin ls "$@" | head ; }

It's similar to the function you have already but with the inclusion of builtin, it guarantees not to get stuck in a loop calling itself. Hope this works!

EDIT: It should be noted that any colour information produced by ls with the --color=auto option won't be carried through the pipe to head.

Upvotes: 3

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