firefox-sessions-backups

#!/bin/bash
USAGE='firefox-sessions-backups [options]
Maintains backups of the Firefox previous sessions file. Useful when the 
previous session files info gets corrupted, or erased by mistake, typically
during an unwanted restart.
Files are stored as recovery.jsonlz4-bak-YYYY-MM-DD.HH.MN.SS
in the directory: ~/.mozilla/firefox/*.default/sessionstore-backups/
To restore a backup, stop firefox, copy it as recovery.jsonlz4 in the same dir,
restart firefox and restore previous session.
Suggestion: run firefox-sessions-backups at boot in your crontab: E.g:
  @reboot /usr/local/bin/firefox-sessions-backups >/dev/null 2>&1 </dev/null
It uses inotify for accuracy and minimal system load, no active waiting.

Options:
  -a accountname
     Uses the account "accountname" instead of the default.
  -k number
     Keeps "number" most recent backups. Defaults to 10.
  -w seconds
     Waits "seconds" after a detected file change before backuping. Defaults to 2.
  -l Lists all available accounts with backupable sessions files and exit.
  -v Verbose mode, otherwise totally silent except for fatal errors.

Note: firefox by default saves the session info every 15s, which can make videos stutter
and can wear SSDs. It is recommended to set "browser.sessionstore.interval" to a larger
value (in microseconds). I use 1800000 to save every 30 minutes. You can also raise
"browser.sessionstore.interval.idle" that is the save interval while user is idle,
by default 1 hour (3600000) to many hours (I use 21600000 = 6h).

v1.0.1 2022-02-19
Source: https://github.com/ColasNahaboo/colas-bash-lib/tree/main/bin/firefox-sessions-backups'

############ Options
REQUIRE=(inotifywait)           # list of required commands
account=
keep=10
delay=2
OPTIONS='a:k:w:l'
# shellcheck disable=SC2015,SC2016,SC2034,SC2046,SC2089,SC2090,SC2219 #########
{ V(){ :;};T(){ :;};v=false;E(){ echo "$@";};En(){ E -n "$@";};VV(){ :;}
err(){ E "***ERROR: $*" >&2; exit 1;};warn(){ E "###Warning: $*" >&2;};nl=$'\n'
OPTIND=1;while getopts ":${OPTIONS}hv?" _o;do case "$_o" in
#----single letter options start-----------------------------------------
    a) account="$OPTARG";;
    k) keep="$OPTARG";;
    w) delay="$OPTARG";;
    l) while read -r d; do
           [[ $d =~ /[.]mozilla/firefox/([^/]+) ]] && echo "  ${BASH_REMATCH[1]}"
       done < <(ls -1t "$HOME/.mozilla/firefox/"*"/sessionstore-backups/recovery.jsonlz4" 2>/dev/null)
       exit 0;;
#----single letter options end-------------------------------------------
v)T(){ local i;{ En "==";for i in "$@";do [[ $i =~ [^_[:alnum:]] ]]&&En " $i"||
En " $i=${!i}";done;E;}>&2;};V(){ E "== $*" >&2;};v=true;;h) E "$USAGE";exit;;
\?)err "Bad option: -$OPTARG, -h for help.";;':')err "Missing arg: -$OPTARG";;
*)err "Bad option: -$_o, -h for help.";esac;done;shift $((OPTIND-1));}
#----end of https://github.com/ColasNahaboo/bashoptions-(getopts)----------v1.0

############ Inits
for r in "${REQUIRE[@]}"; do hash "$r" 2>/dev/null || err "$r required!"; done

if [[ -z $account ]]; then
    account=$(grep -B4 '^Default=1' "$HOME/.mozilla/firefox/profiles.ini" |grep -oP '^Path=\K.*')
    [[ -n $account ]] || err "Could not find a default firefox account. Use -l to list them."
fi
dir="$HOME/.mozilla/firefox/$account/sessionstore-backups/"
cd "$dir" || err "Cannot go into firefox profile dir: $dir"
file="recovery.jsonlz4"

[[ -e $file ]] || sleep "$delay"
tick=$(grep -oP '^user_pref[(]"browser[.]sessionstore[.]interval", *\K[[:digit:]]+' ../prefs.js)
if [[ -n $tick ]]; then
    ((tick /= 1000))
    tickmess=", every $tick seconds"
else
    tickmess=
fi

############ Main loop: wait for change + clean old + backup
V "Starting automated backups of firefox session file$tickmess"
while true; do
    V "Backuping session to $file-bak-$(date +%Y-%m-%d.%H-%M-%S)"
    cp "$file" "$file-bak-$(date +%Y-%m-%d.%H-%M-%S)"
    # shellcheck disable=SC2012
    while read -r f; do
        V "Removing old backup: $f"
        rm -f "$f"
    done < <(ls -1tr "$file-bak-"* 2>/dev/null | head -n -"$keep")
    inotifywait -qq "$file"
    sleep "$delay"              # need at least 0.1s for the file re-creation
done