move from other repo

irc/irc.sh

@@ -0,0 +1,139 @@
+#!/bin/sh
+
+# irc; Deven Blake 2022; Public domain
+# I stopped understanding this at 81 lines.
+
+alias cat='cat -u'
+alias sed='sed -u'
+
+# defaults
+DEFAULT_HOST="example.com"
+PORT=6667
+[ -n "$IRC_QUIT_MESSAGE" ] \
+	|| IRC_QUIT_MESSAGE="Bye bye!"
+
+# defaults (standard-defined)
+URI_FRAGMENT_DELIMITER='#' # RFC 3986
+
+argv0="$0"
+URL="$1"
+
+usage(){
+	printf "Usage: %s [url]\n" "$argv0"
+	exit 1
+}
+
+one_character_per_line(){
+	sed 's/./&\n/g'
+}
+
+host_ex_url(){
+	# filter out scheme URI subcomponent
+	# filter out userinfo URI subcomponent
+	# filter out port
+	# filter out heirarchy path
+	# filter out query
+	# filter out fragment
+	printf "%s\n" "$URL" \
+		| sed 's/.*:\/\///' \
+		| sed 's/.*@//' \
+		| sed 's/:.*$//' \
+		| sed 's/\/.*$//' \
+		| sed 's/\?.*$//' \
+		| sed 's/#.*$//'
+}
+
+port_ex_url(){
+	# filter out scheme URI subcomponent
+	# filter out userinfo URI subcomponent
+	local_url="$(printf "%s\n" "$URL" \
+		| sed 's/.*:\/\///' \
+		| sed 's/.*@//')"
+
+	# check to ensure there Is a port in the URL
+	# this will also catch if we fucked up
+	if ! [ "$(printf "%s\n" "$local_url" \
+			| one_character_per_line \
+			| grep ':' \
+			| wc -l)" \
+		= 1 ]
+	then
+		# give up, gracefully
+		printf "%s\n" "$PORT"
+		return 0
+	fi
+
+	# filter out query URI subcomponent
+	# filter out heirarchy path
+	# filter out everything preceding the port
+	local_url="$(printf "%s\n" "$local_url" \
+		| sed 's/\?.*$//' \
+		| sed 's/\/.*$//' \
+		| sed 's/.*://')"
+
+	printf "%s\n" "$local_url"
+}
+
+username_ex_url(){
+	# only go if there's actually userinfo in the URL
+	# filter out scheme URI subcomponent
+	# filter out everything after userinfo URI subcomponent
+	# filter out password in userinfo, if present
+	printf "%s\n" "$URL" \
+		| grep '@' \
+		| sed 's/.*:\/\///' \
+		| sed 's/@.*$//' \
+		| sed 's/:.*$//'
+}
+
+[ -n "$URL" ] \
+	|| usage
+
+[ -n "$IRC_NICK" ] \
+	|| IRC_NICK="$USER"
+
+# check if URL matches /^irc:\/\//
+if ! printf "%s\n" "$URL" | grep "^irc://" >/dev/null 2>&1; then
+	printf "%s: %s: URL incorrectly formatted or scheme not specified.\n" "$argv0" "$URL"
+	exit 1
+fi
+
+# easy; the fragment is the last part of the URI
+CHANNEL="#$(printf "%s\n" "$URL" \
+	| sed 's/.*#//' )"
+
+# not easy
+PORT="$(port_ex_url)"
+
+# slow, so don't rerun
+a="$(username_ex_url)"
+[ -z "$a" ] \
+	|| IRC_NICK="$a"
+
+HOST="$(host_ex_url)"
+
+[ -n "$HOST" ] \
+	|| HOST="$DEFAULT_HOST"
+
+if ! TEMP="$(mktemp)" || ! TEMP_FIN="$(mktemp)"; then
+	printf "%s: mktemp: Could not make temporary file.\n" "$argv0"
+	exit 1
+fi
+
+# RFC 1459 section 4.1.2
+printf "NICK %s\n" "$IRC_NICK" >"$TEMP"
+
+# RFC 1459 section 4.1.3; USER <username> <hostname> <servername> <realname>
+# not really important
+printf "USER %s 0 0 :\n" "$IRC_NICK" >>"$TEMP"
+
+# RFC 1459 section 4.2.1
+printf "JOIN %s\n" "$CHANNEL" >>"$TEMP"
+
+# RFC 1459 section 4.1.6
+printf "QUIT :%s\n" "$IRC_QUIT_MESSAGE" >"$TEMP_FIN"
+
+# RFC 1459 section 4.4.1
+sed "s/^/PRIVMSG $CHANNEL :/g" \
+	| cat "$TEMP" /dev/stdin "$TEMP_FIN" \
+	| nc "$HOST" "$PORT"