diff (compare two text files)

Compares the contents of two text files. Displays the lines that are different.

 Format:    diff fileordirname1 fileordirname2 Examples:  diff prog1 prog2            diff prog1 /home/janet/dir1            diff /home/janet /home/janet/dir1 

Compares prog1 to prog2. In the second example, compares prog1 to /home/janet/dir1/prog1 if it exists. In the third example, compares all files that exist in both directories.

Displays the lines that differ between the two files. < indicates lines from the first file; > indicates lines from the second file. For example:

 cat fileA John Smith Alice Brown John Huang cat fileB Bob Smith Alice in Wonderland John Huang diff fileA fileB <John Smith <Alice Brown --- >Bob Smith >Alice in Wonderland 

Opt	What It Does	Example
-b	Treat groups of blanks as one	diff -b file1 file2
-B	Ignore blank lines	diff -B prog1 prog2
-c	Display 3 lines surrounding each changed line	diff -c file1 /home/janet
-C n	Display n lines surrounding each changed line	diff -C 5 file1 file1.bak
-i	Ignore case	diff -I report1 report2
-r	Also compare subdirectories	diff -r /home/janet/home/bob
-w	Ignore all white space	diff -w file1 file2
-y	Two-column output	diff -y file2 file5