CODEWITHSUNDEEP
bash
SuperTonic09
SuperTonic09

Reputation: 41

How to suppress this sed in Bash?

#!/bin/bash
set_bash_profile()
{
    local bash_profile="$HOME/.profile"

    if [[ -w $bash_profile ]]; then
        if (grep 'MY_VAR' $bash_profile 2>&1); then
            sed -i '/MY_VAR/d' $bash_profile
        fi
        echo "export MY_VAR=foo" >>$bash_profile
    fi
}

set_bash_profile

Here is the first run:

bash-4.1$ ./set_bash.sh

No output --which is great! And cat shows export MY_VAR=foo was appended to the file. But when executing a second time, I want sed to silently edit $bash_profile without outputting the matching string, like it does here:

bash-4.1$ ./set_bash.sh
export MY_VAR=foo

Upvotes: 0

Views: 525

Answers (1)

KamilCuk
KamilCuk

Reputation: 141493

You get the output from grep on grep 'MY_VAR' $bash_profile 2>&1. grep outputs the matched line in your profile:

export MY_VAR=foo

on stdout. The 2>&1 only forwards stderr to stdout. It's good to use -q option with grep. Also the subshell (...) around the grep is not needed. Try this:

#!/bin/bash
set_bash_profile()
{
    local bash_profile="$HOME/.profile"
    if [ -w $bash_profile ]; then
        if grep -q 'MY_VAR' $bash_profile; then
            sed -i '/MY_VAR/d' $bash_profile
        fi
        echo "export MY_VAR=foo" >>$bash_profile
    fi
}

set_bash_profile

Upvotes: 1

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