diff flags & options

-u, --unified

Output in unified format with context lines.

diff -u old.txt new.txt

diff -u old.txt new.txt > changes.patch

-r, --recursive

Recursively compare any subdirectories found.

diff -r dir1/ dir2/

diff -ru project-v1/ project-v2/

-q, --brief

Report only when files differ, without showing details.

diff -q file1.txt file2.txt

diff -rq dir1/ dir2/

--color

Colorize the output.

diff --color old.txt new.txt

diff -u --color old.txt new.txt

-y, --side-by-side

Output in two columns.

diff -y old.txt new.txt

diff -y -W 120 old.txt new.txt

-w, --ignore-all-space

Ignore all whitespace when comparing lines.

diff -w old.txt new.txt

-B, --ignore-blank-lines

Ignore changes where lines are all blank.

diff -B old.txt new.txt

diff -wB old.txt new.txt