Add nbak plugin to backup all nnn config (#528)

* Add nbak plugin to backup all nnn config

* nbak: check cd, quote env

* nbak: print backup file name

* nbak: add --show option, to show shell config

* nbak: fix shellcheck warning

'type' is POSIX complient, AND we check that we're actually running
bash, but shellcheck can't understand this...
Then '-o' is POSIX complient too, but shellcheck thinks it's "not well defined".

* nbak: variable renames, archive hierarchy changes

* nbak: fix variable expansion

* nbak: remove --show option

* nbak: call interactive bash/zsh to get fun/aliases

* Add nbak entry in plugins/README.md

* nbak: change archive hierarchy

* plugins/README.md: make nbak description shorter

plugins/README.md

@@ -50,6 +50,7 @@ Plugins are installed to `${XDG_CONFIG_HOME:-$HOME/.config}/nnn/plugins`.
 | moclyrics | Show lyrics of the track playing in moc | sh | [ddgr](https://github.com/jarun/ddgr), [moc](http://moc.daper.net/) |
 | mocplay | Append (and/or play) selection/dir/file in moc | sh | [moc](http://moc.daper.net/) |
 | mp3conv | Extract audio from multimedia as mp3 | sh | ffmpeg |
+| nbak | Backs up `nnn` config | sh | tar, awk |
 | nmount | Toggle mount status of a device as normal user | sh | pmount, udisks2 |
 | nuke | Sample file opener (CLI-only by default) | sh | _see in-file docs_ |
 | oldbigfile | List large files by access time | sh | find, sort |

plugins/nbak

@@ -0,0 +1,73 @@
+#!/usr/bin/env sh
+
+# Description: Backup of all nnn config
+#
+# Shell: POSIX compliant
+# Author: Léo Villeveygoux
+
+nnn_aliases="n nnn"
+
+outdir="nnn-$(whoami)@$(hostname)"
+
+outfile="${outdir}.tar.bz2"
+
+shellname="$(basename "$SHELL")"
+
+conffile="config.txt"
+
+configdir="${XDG_CONFIG_HOME:-$HOME/.config}/nnn"
+
+workdir="$PWD"
+
+tempdir="$(mktemp -d)"
+
+mkdir "$tempdir/$outdir"
+
+if [ ! -d "$tempdir" ]; then
+	echo "Can't create work directory." >&2
+	exit 1
+fi
+
+cd "$tempdir/$outdir" || exit 1
+
+# Backing up config dir content
+cp -r "$configdir" . || exit 1
+
+# Environment config
+env | sed "s/'/'\\\\''/" |\
+	awk '/^NNN_/{print "export '\''"$0"'\''"}' > "$conffile"
+
+# Shell functions/aliases
+case "$shellname" in
+	bash)
+		for name in $nnn_aliases ; do
+			if [ "$(bash -ic "type -t $name")" = "function" ] ; then
+				bash -ic "type $name" | tail -n+2 >> "$conffile"
+			elif bash -ic "alias $name" >/dev/null 2>&1 ; then
+				bash -ic "alias $name" >> "$conffile"
+			fi
+		done
+		;;
+	zsh)
+		for name in $nnn_aliases ; do
+			if zsh -ic "functions $name" ; then
+				zsh -ic "functions $name" >> "$conffile"
+			elif zsh -ic "alias $name" ; then
+				echo alias "$(zsh -ic "alias $name")" >> "$conffile"
+			fi
+		done
+		;;
+
+	*)
+		echo "Unknown shell, skipping alias/function checking." >&2
+		;;
+esac
+
+cd .. || exit 1
+
+printf "Saving as '%s' ... " "$workdir/$outfile"
+
+tar caf "$workdir/$outfile" "$outdir" && echo "Done" || echo "Failed"
+
+cd "$workdir" && rm -rf "$tempdir"
+