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Accepted
Manoj Kumar
Asked: 2019-07-17 23:21:57 +0800 CST

How to use grep to match a string with spaces in it?

  • 772

Can anyone help me with this:

I am trying to extract a time stamp, by matching a string. For this am using combination of grep/awk commands. As the sting has 4 spces before [1] and one after, am confused how to work around it. Am new to programming, so need some help here.

IS="$(grep 'Starting    [1] TaskInit' process.log |  awk '{print $4}')"
echo "$IS"

Aim: It should match the string in the process.log file and should print out the time stamp related to that row.

command-line bash grep awk

2 Answers

  1. Best Answer

    The spaces are not the problem here, it should work fine.
    But the brackets [ need to be escaped in regex. So write:

    grep 'Starting    \[1] TaskInit' process.log

    In your case, as you want to match a fixed string and not a regex, you should use grep -F instead. Then you don't need to escape:

    grep -F 'Starting    [1] TaskInit' process.log
    • 6

  2. You just need to escape the square brackets, because they have special meaning:

    grep 'Starting    \[1\] TaskInit' process.log

    In addition I would use only awk for this task, for this purpose you need something like:

    awk '/Starting    \[1] TaskInit/ {print $4}' process.log
    • 3