cmp\_version
============
A script and python module to compare version numbers. Use this to compare the version strings of packages, modules, really anything.
Since version 3.0, cmp\_version supports all kinds of complex version numbers, including those with releases ( like $version-5 ) or Epochs (like 5:$version)
Commandline Tool
----------------
You can use the provided *cmp-version* tool to compare two version strings.
It will print to stdout "-1" if version1 is less/older than version2, "0" if they are equal, and "1" if version1 is greater/newer than version2.
Examples:
$ ./cmp\-version 1.0.1b 1.0.1a
1
$ ./cmp\-version 1.0.1b 1.0.2
\-1
$ ./cmp\-version 1.0 1.0.0
0
Comparing Filenames
-------------------
Without actually scanning the contents of a package, you can from a script compare the versions based on the filenames.
Example:
$ cmp\-version glibc\-6.2.1\-3.x86\_64.rpm glibc\-6.2.3\-1.x86\_64.rpm
\-1
Method Signature
----------------
The cmp\_version module provides a single method, *cmp\_version* which compares two versions "cmp" style (think strcmp or the "cmp" operator in python<3).
def cmp\_version(version1, version2):
'''
cmp\_version \- Compare two version strings, checking which one represents a "newer" (greater) release.
Note that even if two version strings are not equal string\-wise, they may still be equal version\-wise (e.x. 1.0.0 is the same version as 1.0)
@param version1 <str> \- A version string
@param version2 <str> \- A version string
@return <int>
\-1 if version1 is older/less than version2
0 if version1 is equal to version2
1 if version1 is newer/greater than version2
So for example,
cmp\_version('1.0.5b', '1.0.5a') would return 1 because 1.0.5b comes after 1.0.5a
Special Type
------------
cmp\_version provides a special type, "VersionString", which inherits string. All the comparison magic functions are implemented, such that you can directly compare VersionString objects.
Example:
>>> x = VersionString('0.1b2')
>>> y = VersionString('.2b2')
>>>
>>> '0.1b2' < '.2b2' # Show that as strings this version compare gives wrong answer
False
>>> x < y # Show that using VersionString objects, the comparison does work
True
Sorting Lists
-------------
You can sort a list of versions, or filenames containing versions etc like this:
>>> from cmp\_version import cmp\_version, VersionString
>>>
>>> x = ['.9a', '0.9', '0.9.0', '1.2c', '1.1b', '1.b4.0']
>>> sorted(x, key=VersionString)
['0.9', '0.9.0', '.9a', '1.1b', '1.2c', '1.b4.0']
Return value
------------
* 0 is returned when the two versions are equal, even if the strings are not equal (for example "1.0" is the same version as "1.0.0")
* -1 is returned when version1 is older/less than version2
* 1 is returned when version1 is newer/greater than version2.
License
-------
This module is released under Public Domain.
