nixCraft

pixelboss · #1 (**permalink**) 30-01-2009, 03:27 AM

Hi all,

I am trying with next code to check file existence from time to time

Code:

while [ 1 ] 
   do
      if [ ssh ${REMOTE_USER}@${REMOTE_HOST} 'ls "'$RESULT_FILE'" >/dev/null' ]; then
         echo "file $RESULT_FILE exists";
         exit;
         break;
      else
         echo "file $RESULT_FILE does not exist";
         sleep 5
      fi
   done

CASE I
When I tried to create $RESULT_FILE in the remote machine and the code still running, it always give me a false indication about the file even the actual file exist!

CASE II
When I tried to delete the remote file, the code above gives me again a false indication about the file by saying the remote file exists which no exist in reality

I hope if someone can help me with this problem

Thanks in advance.

nixcraft · #2 (**permalink**) 30-01-2009, 06:29 AM

SSH is not designed for this kind of work. It will never work out. You need to use ftp or something else using Perl / Python. FTP would be easy to script and can perform various operations such as rename, delete, upload, download and so on.

r0tt13 · #3 (**permalink**) 28-02-2009, 11:08 AM

not to knock the person that responded, but with linux you can do almost anything you want to if you put some pieces together.

for your instance, you want to use grep. grep is your friend.

since grep uses a 0 or 1 on exit, 0 if it finds something or 1 if it doesnt, you could do something like this....

Code:

CHECKFILE=`ssh <user>@<host> 'ls /path/to/file | grep file > /dev/null; echo $?'`
if [ $CHECKFILE -eq 0 ]
then
echo "file exists"
else
echo "file doesnt exist"
fi

the value of the checkfile variable should echo a 1 or a 0 if you test it manually. you can see how grep can used for alot of different checks. i use it alot in scripts just because the fact that it exits a 1 or a 0 depending.... alot of tools do this but some dont.. its a matter of trial and error.

i hope this helps

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Check if remote files exist (periodically)

Check if remote files exist (periodically)

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