Linux in a Nutshell, 6th Edition

Name

diff

Synopsis

diff [options] file1 file2

Compare two text files. diff reports lines that differ between file1 and file2. Output consists of lines of context from each file, with file1 text flagged by a < symbol and file2 text by a > symbol. Context lines are preceded by the ed command (a, c, or d) that would be used to convert file1 to file2. If one of the files is -, standard input is read. If one of the files is a directory, diff locates the filename in that directory corresponding to the other argument (e.g., diff my_dir junk is the same as diff my_dir/junk junk). If both arguments are directories, diff reports lines that differ between all pairs of files having equivalent names (e.g., olddir/program and newdir/program); in addition, diff lists filenames unique to one directory, as well as subdirectories common to both. See also cmp.

Options

-n

For context and unified diff, print n lines of context. Same as specifying a number with -C or -U.

-a, --text

Treat all files as text files. Useful for checking to see if binary files are identical.

-b, --ignore-space-change

Ignore repeating blanks and end-of-line blanks; treat successive blanks as one.

-B, --ignore-blank-lines

Ignore blank lines in files.

-c

Context diff: print three lines surrounding each changed line.

-C n, --context[=n]

Context diff: print n lines surrounding each changed line. The default context is three lines.

-d, --minimal

Ignore segments of numerous changes and output a smaller set of changes.

-D symbol, --ifdef=symbol

When ...