To track any modification in a specfic file

Shell Programming and Scripting
1

Hi All,

I am a pretty new to programming or scripting. Please help me in my below query.

I want to write a script which can track a file for any kind of modification and if there is any modification then it should move that file or i should say backup that file to another server.

Please help me in writing this script.

Thanks and regards.

2

so, basically, you want first to check

if backup_of_file exists on the server
then
if diff -q fileS
then
backup file
fi
fi

3 
#!/bin/sh

file="/path/to/file"
destdir="/dest/dir"

if [ ! -e $file ]; then
echo "file $file not present"
exit 1;
fi

l=$(stat -f %Sm $file)

while true; do
 c=$(stat -f %Sm $file 2>/dev/null)
  if [ "$l" != "$c" ]; then
   mv "$file" $destdir 2>/dev/null
  fi
 sleep 5
  if [ ! -e $file ]; then
   echo "file $file not present, waiting for $file..."
  fi
done
4

Not exactly.. actually file would be always there but I want to copy it only when somebody change it. And one more thing I need to copy file on different server.

5

you need the "rsync" utility. It can do exactly what you want.

6

sorry if it sounds a stupid query but I am from networking so dont know much about unix stuff.
How rsync would work, will it be running in background tracking and watching one file for any kind of modification?

7

You can download it from here:

rsync

You will have to go through the documentation to tweak for your exact requirements. But here is a sample command that I use to keep my profile and settings in sync across multiple home directories (across multiple servers):

##
## Update the following variables as per your settings.
##
## Path of the rsync utility on the remote server
RSYNC_PATH=/path/to/rsync
## List of files to be backed up every time something changes
FILE_LIST="$home/.profile $home/.functions $home/.vimrc $home/install"
## Remote server
REMOTE_SERVER=my_backup_server
## Remote path where to put the backup files
REMOTE_BACKUP_PATH=/my/backup/path

rsync --links --recursive --rsync-path=$RSYNC_PATH --verbose \
     $FILE_LIST $REMOTE_SERVER:$REMOTE_BACKUP_PATH

Note that before this can be used, you will have to make sure that rsync is installed on both local and the remote server.

You can put this in a script and schedule it in the cron to run on a set frequency based on how often you expect your files to get changed.

~A Programmer