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Numdiff compares putatively similar files line by line and field by field, ignoring small numeric differences or/and different numeric formats.

Numdiff is a program with the capability to appropriately compare files containing numerical fields (and not only). By default, Numdiff assumes the fields are separated by white spaces (blanks, horizontal tabulations and newlines), but the user can also specify its list of separators. When you compare a couple of such files, what you want to obtain usually is a list of the numerical fields in the second file which numerically differ from the corresponding fields in the first file. Well known tools like diff, cmp or wdiff can not be used to this purpose: they can not recognize whether a difference between two numerical fields is only due to the notation or is actually a difference of numerical values. Moreover, you could desire to neglect all small numerical differences too. However, programs like diff and wdiff can not be used to ignore small numerical differences, since they do not even know what a numerical difference is.



Verified by

Verified on


Verified by

Ted Teah

Verified on

5 September 2006

Leaders and contributors

Ivano Primi Maintainer

Resources and communication

AudienceResource typeURI
Savannah (Ref)
Bug Tracking,Developer,Help,
Debian (Ref)

Software prerequisites

Required to buildmake
Required to buildANSI C compliant compiler
Weak prerequisiteGNU Texinfo


"Debian (Ref)" is not in the list (General, Help, Bug Tracking, Support, Developer) of allowed values for the "Resource audience" property.

"Savannah (Ref)" is not in the list (General, Help, Bug Tracking, Support, Developer) of allowed values for the "Resource audience" property.

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