sed: Remove All Except Digits (Numbers) From Input

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How do I remove all (text, special characters, white spaces, tabs etc) from my text file (input) except numbers (digits) using sed command?

You need to use simple regular expression to remove all but numbers from the input. For example, ‘s/^[0-9]*//g’ will remove all but numbers from the input. Type the following command:
$ echo 'This is a test. 123456789 and 2nd number is 34. 3M3i4x5' | sed 's/[^0-9]*//g'
You can remove all except digits from a text file:

sed 's/[^0-9]*//g' input.txt
sed 's/[^0-9]*//g' input.txt > output.txt
sed -i 's/[^0-9]*//g' input.txt

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

3 comment

  1. Good but if I want to delete only numbers (randomly).
    Input 1:
    I am 89 years old.
    Output 1:
    I am years old.
    And
    Input 2:
    I am 2012 years old.
    Output 2:
    I am 9 years old.

    Thanks

    1. I have figured it out. I just removed ^. But if the word contains like 82age or age10 than how it would be possible to remove only numbers.

      Thanks

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