diff

# To diff and patch in single command
diff <file1> <file2> -u | patch

# compare two directories
diff -r dir1/ dir2/

# compare two directories and only tell which files differ
diff -qr dir1/ dir2/

# retain color when piping
diff --color=always

# understanding diff output REF: https://youtu.be/-CiLU9-RAGk?t=169
# diff f1 f2 treats f1 as the original or reference
# green coloring shows additions that are not in f1 but present in f2

# exclude folders
diff -qr --exclude="microsoft-edge" --exclude=.cache /mnt/linn ~ # this exlcudes .config/microsoft-edge

# create a patch file
diff -u file.txt.orig  file.txt > file.patch