From a1990a751cc6e5f9bed598e88723ec02da1b535b Mon Sep 17 00:00:00 2001
From: druckdev <63563978+druckdev@users.noreply.github.com>
Date: Mon, 26 Oct 2020 14:47:14 +0100
Subject: [PATCH] .local/bin:filterHistory: Fix bug and refactor

Fix bug that `cut` only took the second field when splitting on ';'
instead of everything after the first semicolon and thus not properly
handling commands that contain semicolons.

Add die() and hist-sort().
Use here-string instead of process substitution with input redirection.
Rephrase comment.
---
 .local/bin/filterHistory | 44 +++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/.local/bin/filterHistory b/.local/bin/filterHistory
index 824997f..c4dd9ee 100755
--- a/.local/bin/filterHistory
+++ b/.local/bin/filterHistory
@@ -8,25 +8,32 @@
 ##   format of zshs extended history.
 ## An automatic backup is created before deleting that can be used for recovery.
 
-[[ $# -eq 1 ]] || { echo "Specify history file" >&2; exit 1; }
-[[ -e "$1" ]] || { echo "File does not exist" >&2; exit 1; }
-[[ "$(stat -c '%a' "$1")" = "600" ]] || { echo "File does not look like a history file" >&2; exit 1; }
+die() {
+	printf "$1" >&2
+	exit ${2:-1}
+}
 
-# Sort the commands per number of occurrences
-most_used="$(\
-	cut -d';' -f2 "$1" \
+[[ $# -eq 1 ]] || die "Specify a history file.\n"
+[[ -e "$1" ]] || die "File does not exist.\n"
+[[ "$(stat -c '%a' "$1")" = "600" ]] || die "File permissions are off.\n"
+
+# Take a history file per stdin and sort the commands per number of occurrences
+hist-sort() {
+	cut -d';' -f2- \
 	| sort \
 	| uniq -c \
-	| sort -nr \
-)"
+	| sort -nr
+}
+
+most_used="$(hist-sort <"$1")"
 
 declare -a commands
 if command -v fzf >/dev/null 2>&1; then
 	# Let the user pick in fzf from the most used commands
-	readarray -t commands < <(\
+	readarray -t commands <<<"$(
 		fzf -m --reverse --height 50% <<<"$most_used" \
-		| sed -E 's/^[ \t]*[0-9]+ //' \
-	)
+		| sed -E 's/^[ \t]*[0-9]+ //'
+	)"
 else
 	echo "Most used commands:"
 	offset="$(head -1 <<<"$most_used" | sed -E 's/^( *[0-9]+).*$/\1/' | wc -m)"
@@ -46,7 +53,7 @@ fi
 printf '%s\n' "${commands[@]}" | column -x
 echo "Please confirm the deletion of these commands in $1 ('yes')"
 read yn
-[[ "$yn" = "yes" ]] || exit 1
+[[ "$yn" = "yes" ]] || die
 
 tempd="$(mktemp -d)"
 cp "$1" "$tempd/$(basename "$1")"
@@ -55,16 +62,15 @@ echo
 
 for c in "${commands[@]}"; do
 	# Escape all characters that sed could misinterpret.
-	pattern="^: [0-9]+:[0-9]+;$(sed -E 's/[./?+|()*\\^$]|\[|\]/\\&/g' <<<"$c")\$"
-	# Find first occurrence of the command in the history file
-	first="$(grep -Enm1 "$pattern" "$1" | cut -d: -f1)"
+	pat="^: [0-9]+:[0-9]+;$(sed -E 's/[./?+|()*\\^$]|\[|\]/\\&/g' <<<"$c")\$"
+	# Find line number of first occurrence of the command in the history file
+	first="$(grep -Enm1 "$pat" "$1" | cut -d: -f1)"
 
-	# Delete all lines beginning from the line after the first occurrence that
-	# contain (exactly) the command.
-	sed -Ei "$((first + 1)),\$ { /$pattern/d }" "$1"
+	# Delete all occurrences of the command except for the first one
+	sed -Ei "$((${first} + 1)),\$ { /$pat/d }" "$1"
 	echo "$c deleted"
 done
 
 echo
 echo "Following commands were deleted:"
-diff "$1" "$tempd/$(basename "$1")" | grep "^>" | cut -d\; -f 2 | sort | uniq -c | sort -nr
+diff "$1" "$tempd/$(basename "$1")" | grep "^>" | hist-sort