Question

This bash script is supposed to remove leading whitespace from grep results:

#!/bin/bash
grep --color=always $@ | sed -r -e's/:[[:space:]]*/:/'

But it doesn’t match the whitespace. If I change the substitution text to “-“, that shows up in the output, but it still never removes the whitespace. I’ve tried it without the “*”, escaping the “*”, with “+”, etc, but nothing works. Does anyone know why not?

(I’m using sed version 4.2.1 on Ubuntu 12.04.)

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Thanks all, this is my modified script, which shows grep color and also trims leading blanks:

#!/bin/bash
grep --color=always $@ | sed -r -e's/[[:space:]]+//'

Answer 1

You need to remove the –color option for this to work. The color codes confuse sed:

grep  $@ | sed -r -e's/:[[:space:]]*/:/'