Watches a file for changes and executes a command every time it does.

exec-changes.sh

#! /bin/bash

# Watches a file for changes and executes a command every time it does.
# Need to enclose COMMAND in quotes, script dumbly calls $2.
#
# USE:
#    exec-changes FILENAME COMMAND
 
LAST=`stat -c '%Y' $1`

while true; do
    CURRENT=`stat -c '%Y' $1`
    if [ $LAST -ne $CURRENT ]; then
        echo "`date`: file changed"
        `$2`
        LAST=$CURRENT
    fi
    sleep 1
done