From d06e0d3abefa188affccb2876e9026719c02112c Mon Sep 17 00:00:00 2001
From: Pieds-Nus <pieds.nus@zaclys.net>
Date: Mon, 19 Sep 2022 21:56:30 +0000
Subject: [PATCH] swapctl.sh : added support to update fstab

---
 swapctl.sh | 68 ++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 59 insertions(+), 9 deletions(-)

diff --git a/swapctl.sh b/swapctl.sh
index d82da4b..79eed19 100644
--- a/swapctl.sh
+++ b/swapctl.sh
@@ -1,5 +1,6 @@
 #!/bin/bash
 
+sep="\n\t#############\n"
 usage="$0 -d DIR -n NAME -s SIZE -p PRIO add|remove
 Add or remove swapfiles to micro-manage disk usage.
   -d DIR  : set DIRectory to place swapfile in. Default: /mnt
@@ -8,13 +9,17 @@ Add or remove swapfiles to micro-manage disk usage.
   -p PRIO : Priority to use with swapon. Range from 0 to 1000. Default: 500
   -h      : Display this help and exit."
 
-test $# -eq 0 && ( echo -e "$usage" ; echo "You must provide either 'add' or 'remove' !" ; exit 1 )
+if test $# -eq 0 ; then
+	echo -e "$usage"
+	echo "You must provide either 'add' or 'remove' !"
+	exit 1
+fi
 
 SWAP_FOLDER="/mnt"
 SWAP_FILENAME="swapfile"
-SWAP_SIZE="12"	#in MB
-SWAP_PRIO_MAX=500	#range 0..1000
-SWAP_PRIO_INC=10
+SWAP_SIZE="1024"	#in MB
+SWAP_PRIO_MAX=750	#range 0..1000
+SWAP_PRIO_INC=50
 
 while getopts hp:s:n:d: arg ; do
 	case $arg in
@@ -33,15 +38,16 @@ if test "$1" = "add" ; then
 	
 	N=$(ls $SWAP_FOLDER/$SWAP_FILENAME* | wc -l)
 	swapfile=$SWAP_FOLDER/$SWAP_FILENAME$N
+	prio=$((($SWAP_PRIO_MAX - $N * $SWAP_PRIO_INC)))
 	
-	echo "Creating swapfile: $swapfile"
+	echo -e "$sep Creating swapfile: $swapfile$sep"
 	
 	sudo dd if=/dev/urandom of=$swapfile bs=1M count=$SWAP_SIZE status=progress
 	sudo chmod 0600 $swapfile
 	sudo mkswap $swapfile
-	sudo swapon -p $((($SWAP_PRIO_MAX - $N * $SWAP_PRIO_INC))) $swapfile
+	sudo swapon -p $prio $swapfile
 	
-	echo -e "\n\n\n\n"
+	echo -e "\n\n"
 	sudo swapon
 	
 elif test "$1" = "remove" ; then
@@ -49,11 +55,55 @@ elif test "$1" = "remove" ; then
 	N=$(ls $SWAP_FOLDER/$SWAP_FILENAME* | wc -l)
 	swapfile=$SWAP_FOLDER/$SWAP_FILENAME$((($N - 1)))
 	
-	echo "Removing swapfile: $swapfile"
+	echo -e "$sep Removing swapfile: $swapfile$sep"
 	
 	sudo swapoff $swapfile && sudo rm $swapfile
 	
-	echo -e "\n\n\n\n"
+	echo -e "\n\n"
 	sudo swapon
 	
 fi
+
+echo -e "$sep Editing /etc/fstab accordingly$sep"
+
+tmpfile=/tmp/swapctl.fstab
+
+if test $1 = "add" ; then
+	cat /etc/fstab > $tmpfile
+	echo -e "$swapfile\t\t\t\t\t\t\t\t\tnone\t\t\tswap\tsw,pri=$prio\t\t\t0\t\t0" >> $tmpfile
+else
+	cat /etc/fstab | grep -v $swapfile > $tmpfile
+	
+fi
+
+echo -e  "# The lines below this one will be the new fstab file : \n\n $(cat $tmpfile)" | more
+
+while true ; do
+	
+	echo -e "$sep What to do with this fstab ?"
+	echo -e "[ \t\e[4ma\\e[0mccept changes | \e[4me\e[0mdit file | dis\e[4mc\e[0mard changes | show \e[4md\e[0miff ]"
+	read prompt
+	
+	case $prompt in
+		a|accept)
+			sudo mv /etc/fstab.2 /etc/fstab.3
+			sudo mv /etc/fstab.1 /etc/fstab.2
+			sudo mv /etc/fstab /etc/fstab.1
+			sudo mv $tmpfile /etc/fstab
+			echo -e "$sep Changes accepted. New contents of /etc/fstab :$sep"
+			cat /etc/fstab | more
+			break
+		;;
+		e|edit)
+			${EDITOR:-nano} $tmpfile
+		;;
+		c|discard)
+			echo "$sep Changes discarded. /etc/fstab remains unchanged.$sep"
+			break
+		;;
+		d|diff)
+			echo -e "\n\n\tdiff\t\t/etc/fstab\t\t\t\t\t\t/tmp/swapctl.fstab\n"
+			diff --tabsize=4 -E -Z -b -t -y /etc/fstab /tmp/swapctl.fstab | more
+		;;
+	esac
+done