Recall

#!/bin/bash
#
# Extensive shell instrumentation, to keep long-term record of
# shell activity.  Produces state dumps at regular intervals
# which are usable via the Reconstruct script to restore an
# exact replica of a once-current session.
#
if [ -z "$RECALL_HIST" ]
then
  export RECALL_HIST="`history 1 | awk '{ print $1 }'`"
  if [ -z "$RECALL_HIST" ]
  then
    if [ -s "$HISTFILE" -a -r "$HISTFILE" ]
    then
	# ignore history timestamps
	export RECALL_HIST=$[ `grep -va '^#' $HISTFILE | wc -l` - 2 ]
    else
	export RECALL_HIST=1
    fi
  fi
fi
export RECALL_INTERVAL=${RECALL_INTERVAL:-30}
export RECALL_MAXDEPTH=${RECALL_MAXDEPTH:-2}
export RECALL_DUMP=${RECALL_DUMP:-~/.TR/dump}
export RECALL_TTY="`tty | sed 's;/dev/;;'`"
#
# Alarm generator.
function recall_alrm ()
{
    #
    # Directories sometimes disappear, so post
    # the pending ALRM from / using a subshell.
    f=/tmp/.recall-alrm.$$
    ( cd /
      echo "kill -ALRM $$ 2>/dev/null # $DISPLAY $RECALL_TTY" |
      at now + $[$RECALL_INTERVAL+($RANDOM % 10)]minutes ) > $f 2>&1
    export RECALL_NEXT_ALRM="`grep -va 'warning:' $f | head -1 | sed -e 's/^[^ ]*job \([0-9]\+\) .\+$/\1/'`"
    rm -f $f
    unset f
}
#
# State dumper.
function recall_dump ()
{
  #
  # Restart for next time.
  if [ "$RECALL_EXIT" != yes ] ; then
    recall_alrm
  else
    echo recall_dump: final.
    if [ "$RECALL_NEXT_ALRM" ] ; then
      atrm "$RECALL_NEXT_ALRM"
    fi
  fi
  #
  # We dump only if there's been activity.
  newhist="`history 1 | awk '{ print $1 }'`"
  if [ $newhist -ne $RECALL_HIST ]
  then
    #
    # The dir may not be ready yet.
    workdir="$RECALL_DUMP"/"`hostname --short`"/"$RECALL_TTY"
    if [ ! -d "$workdir" ]
    then
      mkdir -p "$workdir"
      chmod 700 "$RECALL_DUMP"
    fi
    timestamp="`date '+%Y~%m~%d-%H:%M:%S'`"
    #
    # Bury this background invocation THREE shells deep (triple paren)
    # to avoid the job being seen as a product of the topmost shell:
    # Note placement of backgroundifying `&'.
    ( ( (   echo --pid=$$
	    echo --tty="$RECALL_TTY"
	    geometry="`stty -a < /dev/$RECALL_TTY | grep columns | sed -e 's/^.*rows \([0-9]*\); columns \([0-9]*\).*$/\2x\1/'`"
	    echo -geometry "$geometry"
	    echo -e '\n--dirstack-begin'
	    builtin dirs -l
	    echo -e '--dirstack-end\n\n--history-begin'
	    history $[$newhist-$RECALL_HIST]
	    echo -e '--history-end\n\n--environment-begin'
	    # rather than get environment with env(1), we get it directly from proc.
	    # this allows us to sort after differentiating NUL-terminated NAME=value pairs
	    # from embedded NLs within variable values, by temporarily substituting \377.
	    RECALL_TIMESTAMP="$timestamp" tr '\n' '\377' < /proc/$$/environ | tr '\0' '\n' | sort | egrep -av '^(SSH_|module=|BASH_FUNC_)' | tr '\377' '\n'
	    echo -e '--environment-end\n\n--processes-begin'
	    ps uwwwt"$RECALL_TTY"
	    echo -e '--processes-end'
	    if [ "$RECALL_DIRLIST" ]
	    then
		echo -e '\n--changes-begin'
		( find . ${RECALL_DIRLIST//:/ } -xdev \
		    -maxdepth "$RECALL_MAXDEPTH" -mtime -1 -type f -print |
		    egrep -iva '/\.cache/|/cache|/\.zoom/data' |
		    xargs ls -ld ) 2>/dev/null
		echo -e '--changes-end'
	    fi
	) < /dev/null > "$workdir"/"$timestamp"
	case "$RECALL_MAIL" in
	    1 | [Yy] | yes | YES | on | ON)
                # must get rid of ESC, or else mailx uses base64.
		tr '\033' '^' < "$workdir"/"$timestamp" | mailx -s "Total Recall: $timestamp $HOSTNAME $RECALL_TTY" "$USER"
		rm -f "$workdir"/"$timestamp"
		;;
	    *)
		;; # nothing more to do.
	esac ) & )
    export RECALL_HIST="$newhist"
  fi
  if [ "$RECALL_EXIT" = yes ] ; then
    # stty must complete before pty disappears.
    sleep 0.2
  fi
  unset newhist timestamp workdir
}
#
# We will pick up on this with alarm signals and on exit.
trap "RECALL_EXIT=yes recall_dump" EXIT
trap "recall_dump" ALRM
#
# Replacement "atq" command, to pick out command sets.
alias atq="/usr/bin/atq | sort -n | while read j x ; do echo \$j'	'\$x ; at -c \"\$j\" | sed -e '1,/<<.*\(random\|DELIMIT\)/d' -e '/DELIMIT/d' -e '/^$/d' -e 's/^/	/' ; done"
#
# Provide an alias to turn it all off.
alias noRecall='trap exit && trap alrm && atrm "$RECALL_NEXT_ALRM" && unset RECALL_NEXT_ALRM && unalias noRecall'
#
# And we'll start the process now.
recall_alrm