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diff - differential file comparator


diff [-efbwr] file1... file2


The diff command tells what lines must be changed in two files to bring them into agreement. If one file is a directory, then a file in that directory with basename the same as that of the other file is used. If both files are directories, similarly named files in the two directories are compared by the method of diff for text files and cmp otherwise. If more than two file names are given, then each argument is compared to the last argument as above. The normal output contains lines of these forms:


The -e option produces a script of a, c and d commands for the Unix system editor ed, which will recreate file2 from file1.


The -f option produces a similar script, not useful with ed, in the opposite order. It may, however, be useful as input to a stream-oriented post-processor.


The -b option causes trailing blanks (spaces and tabs) to be ignored and other strings of blanks to compare equal.


The -w option causes all white-space to be removed from input lines before applying the difference algorithm.


The -r option causes diff to process similarly named subdirectories recursively.



See Also



Editing scripts produced under the -e or -f option are naive about creating lines consisting of a single '.'.

When running diff on directories, the notion of what is a text file is open to debate.

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