fish-shell/share/functions/history.fish

#
#Deletes an item from history
#

function history --description "Deletes an item from history"

	set -l argc (count $argv)
	set -l prefix_args ""
	set -l contains_args ""

	set -l cmd print

	set -l search_mode none

	set -l pager less
	if set -q PAGER
		set pager $PAGER
	end

	if test $argc -gt 0
		for i in (seq $argc)
			switch $argv[$i]
			case --delete
				set cmd delete
			case --prefix
				set search_mode prefix
				set prefix_args $argv[(math $i + 1)]
			case --contains
				set search_mode contains
				set contains_args $argv[(math $i + 1)]
			case --save
				set cmd save
			case --clear
				set cmd clear
			case --search
				set cmd print
			case --merge
				set cmd merge
			case --
				set -e argv[$i]
				break
			case "-*" "--*"
				printf ( _ "%s: invalid option -- %s\n" ) history $argv[1] >& 2
				return 1
			end
		end
	else
		#Execute history builtin without any argument
		if status --is-interactive
			builtin history  | eval $pager
		else
			builtin history
		end
		return
	end

	switch $cmd
	case print
		# Print matching items
		# Note this may end up passing --search twice to the builtin,
		# but that's harmless
		builtin history --search $argv

	case delete
		# Interactively delete history
		set -l found_items ""
		switch $search_mode
		case prefix
			set found_items (builtin history --search --prefix $prefix_args)
		case contains
			set found_items (builtin history --search --contains $contains_args)
		case none
			builtin history $argv

			#Save changes after deleting item
			builtin history --save
			return 0
		end

		set found_items_count (count $found_items)
		if test $found_items_count -gt 0
			echo "[0] cancel"
			echo "[1] all"
			echo

			for i in (seq $found_items_count)
				printf "[%s] %s \n" (math $i + 1) $found_items[$i]
			end

			read --local --prompt "echo 'Delete which entries? > '" choice
			set choice (string split " " -- $choice)

			for i in $choice

				# Skip empty input, for example, if the user just hits return
				if test -z $i
					continue
				end

				#Following two validations could be embedded with "and" but I find the syntax kind of weird.
				if not string match -qr '^[0-9]+$'
					printf "Invalid input: %s\n" $i
					continue
				end

				if test $i -gt (math $found_items_count + 1)
					printf "Invalid input : %s\n" $i
					continue
				end

				if test $i = "0"
					printf "Cancel\n"
					return
				else
					if test $i = "1"
						for item in $found_items
							builtin history --delete $item
						end
						printf "Deleted all!\n"
					else
						builtin history --delete $found_items[(math $i - 1)]
					end

				end
			end
			#Save changes after deleting item(s)
			builtin history --save
		end
	case save
		#Save changes to history file
		builtin history $argv
	case merge
		builtin history --merge
	case clear
		# Erase the entire history
		echo "Are you sure you want to clear history ? (y/n)"
		read ch
		if test $ch = "y"
			builtin history $argv
			echo "History cleared!"
		end
	end
end