CODEWITHSUNDEEP
bash
h2459jl
h2459jl

Reputation: 415

Suppress output based on variable

I have a script with an optional verbosity argument. Depending on its value I want to suppress output (pushd in example below, but in reality other, mostly git commands). Example:

verb=1
# pushd optionally outputs path (works but too long)
if [ $verb ]; then
  pushd ..
else
  pushd .. > /dev/null
fi
popd > /dev/null  # the same if.. would be needed here

What I am looking for is something along:

push .. $cond  # single line, outputing somehow controlled directly
popd $cond     # ditto

Anybody can help? Thanks,

Hans-Peter

Upvotes: 0

Views: 352

Answers (2)

cdarke
cdarke

Reputation: 44344

Use a different file descritor to redirect to:

if (( $verb ))
then
    exec 3>&1
else
    exec 3>/dev/null
fi

push .. >&3
popd >&3

This way, the condition is only tested once, at the beginning, rather then every time you do redirection.

Upvotes: 1

choroba
choroba

Reputation: 241768

You can redirect the output to a function whose definition depends on the $verb:

#! /bin/bash

verb=$1

if [[ $verb ]] ; then
    verb () {
        cat
    }
else
    verb () {
        :     # Does nothing.
    }
fi

echo A | verb

Upvotes: 2

Related Questions