cacheit.sh

#! /bin/bash
DEBUG="false";
MAXCACHEAGE="60";
COMMAND="false";

while getopts "da:c:" optionName; do
        case "$optionName" in
                d)
                        DEBUG="true"
                        ;;
                a)
                        MAXCACHEAGE=$OPTARG;
                        ;;
                c)
                        COMMAND=$OPTARG;
                        ;;
                [?])
                        echo "$0 - (C) 2012 Fred Smith <derf@derf.us>";
                        echo "Usage: $0 -a <max cache age> -c \"<command>\"";
                        exit;
         ;;
   esac
done


CLEANCOMMAND=$(echo "$COMMAND" | sed -e 's/ /_/' -e 's/\///');
CACHEFILE="/tmp/cacheof-$CLEANCOMMAND.txt";
$DEBUG && echo "Cache File is: $CACHEFILE";

if test -f $CACHEFILE; then {
   CACHEAGE=$(($(date +%s) - $(stat -c '%Y' "$CACHEFILE")))
} else {
   CACHEAGE="100000";
} fi;

if test $CACHEAGE -lt $MAXCACHEAGE; then {
   $DEBUG && echo "using cached version; $CACHEAGE seconds old."
   cat $CACHEFILE;
   exit;
} fi;

$COMMAND > $CACHEFILE;
cat $CACHEFILE;

[15:42:50] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
Fri Mar 2 15:44:52 EST 2012
[15:44:52] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 2 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:44:54] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 4 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:44:56] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 6 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:44:58] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 7 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:44:59] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 8 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:45:00] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 9 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:45:01] derf@Ganymede[/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
using cached version; 9 seconds old.
Fri Mar 2 15:44:52 EST 2012
[15:45:01] derf@Ganymede[~/bin]$ cacheit -a 10 -d -c "date"
Cache File is: /tmp/cacheof-date.txt
Fri Mar 2 15:45:02 EST 2012