[SOLVED] remort loging, check for a file existince and display a message (if condition)

procfs · 05-31-2010, 12:28 AM

Hi I wan to ssh and check for a file, I hve came up with following, and its not working,

Is this possible or do I have to do this in a another way.

if [ [ `ssh root@myhost -C [ -a /vol1/backup/file1 ]` ]
then

echo "File exist"
else
echo "File not found"

fi

Thanks and bet regards

sohail0399 · 05-31-2010, 01:13 AM

there is ] missing but there is still syntax error

colucix · 05-31-2010, 01:35 AM

Well... first to test a command you don't need the square brackets nor the back ticks, e.g.

Code:

if command
then
  do something
fi

here the exit status of the command is used as true (0 = success) or false (1 = failure). Second, I have some doubt about the ssh command you used. In openssh the -C option has a totally different meaning from "execute a command to the remote machine". What version of ssh are you using? Is this a linux box?

Here is what you can do if using openssh, to test the existence of a regular file on the remote machine:

Code:

if ssh user@host "test -f /path/to/remote/file"
then
  echo file exists
else
  echo file not found
fi

Hope this helps.

procfs · 05-31-2010, 01:58 AM

Hi Guys, thanks for the reply, I've changed and removed the extra ] from the code, but even though the file exist it goes to echo "File does not exist" part

My OS is Redhat 5.4 and open ssh OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 (Sorry about that)

And my changed code is

if [ `ssh root@myhost -C "test -f /vol1/backup/file1"` ]
then

echo "File exist"
else
echo "File not found"

fi

colucix · 05-31-2010, 02:22 AM

Maybe my post was not clear enough, but you should end up with this:

Code:

if ssh root@myhost "test -f /vol1/backup/file1"
then
  echo "File exist"
else
  echo "File not found"
fi

The -C option of ssh means "Requests compression of all data (including stdin, stdout, stderr, and data for forwarded X11 and TCP connections)" and most likely it is not necessary. See man ssh for details.

Regarding the syntax of if/then to test commands (not expressions) see here, where you read

Quote:

An if can test any command, not just conditions enclosed within brackets.

procfs · 05-31-2010, 02:32 AM

Hi colucix, you are right, I understood your answer wrong, thanks for the help its working

Bast Regards