Easily create backups of files with a .bak extension (also adds a trailing number if the file already exists)

bak

#!/bin/bash

for filepath in $@; do
	if [[ -f "$filepath" ]]; then
		filepath_bak=$filepath.bak
		if [[ -f "$filepath_bak" ]]; then
			i=1
			filepath_bak_i=$filepath_bak".$i"
			while [[ -f "$filepath_bak_i" ]]; do
				((i++))
				filepath_bak_i=$filepath_bak".$i"
			done
			filepath_bak=$filepath_bak_i
		fi
		echo -n "$filepath => "
		cp $filepath $filepath_bak
		echo "$filepath_bak"
	else
		echo "$filepath: not a file"
	fi
done