CODEWITHSUNDEEP
bashsed
Dom_TC
Dom_TC

Reputation: 48

Editing line in config file with Sed

I'm sure this is really simple, but I have been having some issues.

I'm trying to create a bash script to update a line in a config file based on a argument passed to it.

The config file looks like this:

//globalConfig.php
'General' => array(
    'env_name' => 'Global',             
    'project_name' => 'ProjectName',    
    'version' => 'x.x.x'                
),

And I am trying to create a script that changes the 'version' value. The script I have ended up with, which doesn't work is this:

#!/usr/bin/env bash

sed -i "s/^\'version\'.*/\'version\' => \'$1\'/" globalConfig.php

Thanks for your help!

Upvotes: 1

Views: 477

Answers (1)

mklement0
mklement0

Reputation: 437111

Try (using GNU sed, as implied by your question):

sed -i -r "s/^(\s*'version'\s*=>).*/\1 '$1'/" globalConfig.php

  • -r enables support for extended regular expressions, which allows for definition of capture group (\s*'version'\s*=>) using the expected modern syntax.

    • \s* matches any (potentially empty) run of whitespace, making for more flexible matching.

  • \1 in the replacement operand refers to what the first (and only) capture group captured, which makes it unnecessary to repeat the 'version' => part.

  • Note that $1 is expanded by the shell, up front, to supply the replacement value, which assumes that the value of $1 doesn't break the script that sed sees as a result; specifically, $1 must not contain (unescaped) / and \ instances.

As for what you tried:

  • Inside "..." (a double-quoted shell string), ' chars. can be used as-is - do not \-escape them.

  • Since ^ matches the start of the line, 'version' won't be matched immediately after, because there is intervening whitespace in your sample input.

Upvotes: 1

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