If File has been updated, do something??

Shell Programming and Scripting
1

Put this together from somewhere else on the forums, just modified it and added the loop.

#!/bin/ksh

localFile=$1
remoteFile=$2

#source FTP parameters
. .ftp_put.cfg

mylog=ftp_session.log
echo "$(date "+%H:%M:%S") - Attempt to FTP $1 to $2" > $mylog
machine="server1 server2 server3 server4"
count=0
# do the FTP put

for machine in $machine
do
ftp -i -n <<EOF >> $mylog
open $machine
user $FTP_LOGIN $FTP_PASSWORD
put $localFile $remoteFile
ls $remoteFile
quit
EOF
count=`expr $count + 1`
done

This script gets called by another script through a cron job every 5 minutes:

/tmp/abcQATest/abcMoveTest.sh archive.tar /tmp/archive.tar

Anyways, I was wondering if there was any way of making it a little better. Currently this simply ftp's that static file every 5 minutes, regardless of if the file has been updated or not. The way it works now is if someone needs to make an update to the 4 server's that this script FTP's to, they simply drop their archive file(named archive.tar) to the /tmp/abcQATest/ directory, and then within 5 minutes the crontab runs and ftp's their file to server 1-4 at the /tmp/archive.tar location.

Is there any way to set this up so it only ftp's the file if it's been updated since the last time the ftp ran? That way, if it gets updated, it get's FTP'd once, but then it doesn't get FTP'd again unless the file's been changed?

Then on the other 4 servers, I also need something like this:

If /tmp/archive.tar has been updated

do something
.
.
else
endif

The do something part is just a couple quick moves, extracts and deletes, that's no big deal. It's If statement I am stumped on.

2

cat file1 > file2

lets say file1 gets updated.

diff file1 file2 > file3.

if [ -s file3 ]
do something. (in your case FTP)
fi

thanks
Sumeet

3

Script:

diff archive.tar backup.tar > tmp
if [ -s tmp ]; then
/tmp/abcQATest/abcMoveTest.sh archive.tar /tmp/archive.tar
echo "Files different, transferring files"
else
echo "Files the same, exiting";
fi

Results:

/tmp/abcQATest>./autoMoveScript.sh
Binary files archive.tar and backup.tar differ
Files the same, exiting
/tmp/abcQATest>

The binary files do differ, but then for some reason it always goes to the second part of the if statement.

4

I believe you have to use the -a parameter on the diff command to compare binaries.

5

It worked, but now even if archive.tar and backup.tar are the same, it says their different and it runs the first block, instead of just doing the echo which states "Files the same, exiting";

diff archive.tar backup.tar > tmp
if [ -a tmp ]; then
/tmp/abcQATest/abcMoveTest.sh archive.tar /tmp/archive.tar
echo "Files different, transferring files"
cat archive.tar > backup.tar
else
echo "Files the same, exiting";
fi
6

Here's my final code I got working.

cmp archive.tar backup.tar > /dev/null
if [[ $? -eq 1 ]]; then
/tmp/abcQATest/abcMoveTest.sh archive.tar /tmp/archive.tar
echo "Files different, transferring files"
cat archive.tar > backup.tar
else
echo "Files the same, exiting";
fi