1. diff compare files line by line
example:
diff file1 file2
2. diff -r recursively compare directories
example:
diff -r dir1 dir2
3. compare two sorted files line by line
comm file1 file2
-1 suppress lines unique to file1.
-2 suppress lines unique to file2.
-3 suppress lines that appear in both files.
example:
comm -12 file1 file2
Print only lines present in both file1 and file2.
comm -3 file1 file2
Print lines in file1 not in file2, and vice versa.
4. meld is a visual diff and merge tool.
It helps you compare files, directories, and version controlled projects. Free and easy to install. It is packaged for most Linux/Unix distributions, including Fedora, Ubuntu, and Suse.
example:
meld file1 file2
