Shell Script Version Compare (vercmp)

Here is something useful. A very short shell script to compare standard version numbers of the form ##.##.## with up to four segments. It returns the difference of the first differing segment just like strcmp.

#!/bin/sh
 
expr '(' "$1" : '\([^.]*\)' ')' '-' '(' "$2" : '\([^.]*\)' ')' '|' \
    '(' "$1.0" : '[^.]*[.]\([^.]*\)' ')' '-' '(' "$2.0" : '[^.]*[.]\([^.]*\)' ')' '|' \
    '(' "$1.0.0" : '[^.]*[.][^.]*[.]\([^.]*\)' ')' '-' '(' "$2.0.0" : '[^.]*[.][^.]*[.]\([^.]*\)' ')' '|' \
    '(' "$1.0.0.0" : '[^.]*[.][^.]*[.][^.]*[.]\([^.]*\)' ')' '-' '(' "$2.0.0.0" : '[^.]*[.][^.]*[.][^.]*[.]\([^.]*\)' ')'

Update: Added zeros to deal with unbalanced version compares

Code, shell, version

This entry was posted on April 5, 2010, 10:18 pm and is filed under Uncategorized. You can follow any responses to this entry through RSS 2.0. You can leave a response, or trackback from your own site.

Comments (5)
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#1 by Kelly Beck on April 30, 2010 - 10:22 am

Have not checked in on the blog recently; so, I just got your comment. Awesome sauce! Extra points for brevity.

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#2 by Petri Lehtinen on March 25, 2011 - 6:03 am

This would be extremely useful, but it seems to fail when comparing .e.g “1.4″ and “1.4.9″

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#3 by A R Baboon on March 25, 2011 - 10:07 am

Petri Lehtinen :

This would be extremely useful, but it seems to fail when comparing .e.g “1.4″ and “1.4.9″

Ok I think I solved that problem. I think it will work for all expected inputs of one to four positive integers tightly packed with dots.

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#4 by Petri Lehtinen on March 29, 2011 - 6:00 am

Yeah, I fixed it the same way actually before reading your response. Thanks!

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#5 by Bryan on May 2, 2011 - 1:09 pm

Looks like a solid string of code to me. Should be useful, thanks!

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