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Asked: 2026-06-14T08:01:25+00:00

This is a really simple RegEx that isn’t working, and I can’t figure out

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This is a really simple RegEx that isn’t working, and I can’t figure out why. According to this, it should work.

I’m on a Mac (OS X 10.8.2).

script.sh

#!/bin/bash
ZIP="software-1.3-licensetypeone.zip"
VERSION=$(sed 's/software-//g;s/-(licensetypeone|licensetypetwo).zip//g' <<< $ZIP)

echo $VERSION

terminal

$ sh script.sh
1.3-licensetypeone.zip
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1 Answer

  1. Editorial Team

    Looking at the regex documentation for OS X 10.7.4 (but should apply to OP’s 10.8.2), it is mentioned in the last paragraph that

    Obsolete (basic) regular expressions differ in several respects. | is an ordinary character and there is no equivalent for its functionality…

    … The parentheses for nested subexpressions are \(' and )’…

    sed, without any options, uses basic regular expression (BRE).

    To use | in OS X or BSD’s sed, you need to enable extended regular expression (ERE) via -E option, i.e.

    sed -E 's/software-//g;s/-(licensetypeone|licensetypetwo).zip//g'

    p/s: \| in BRE is a GNU extension.

    Alternative ways to extract version number

    1. chop-chop (parameter expansion)

      VERSION=${ZIP#software-}
VERSION=${VERSION%-license*.zip}

    2. sed

      VERSION=$(sed 's/software-\(.*\)-license.*/\1/' <<< "$ZIP")

      You don’t necessarily have to match strings word-by-word with shell patterns or regex.

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