topic Re: rsh/sshWeird Behaviour in Operating System - HP-UX

rsh/sshWeird Behaviour

Alzhy — Fri, 16 Apr 2004 07:50:19 GMT

One of my users is wondering about this behaviour:

He has the following command that he tries to run via rsh or ssh from another Unix or Windows machine:

rsh unixsvr "PID=`ps -ef |grep -w SomeApp123|grep -v grep|awk '{print $2}'`;echo 'I will KILL:$PID'"

This command will eventually be what will be tied to a Java/TCL/tk Button. However, it seems the remote execution does not do what it is required to do... In the above example, it only returns "I will KILL:"

Of course, manually executing the command on the UNIX server works!!

I am stumped. Any ideas? Same behaviour for ssh...

Re: rsh/sshWeird Behaviour

Jdamian — Fri, 16 Apr 2004 07:59:28 GMT

The problem is the following

`ps -ef |grep -w SomeApp123|grep -v grep|awk '{print $2}'`

is executed on local host, not in remote host.
Before launching rsh command, the shell will run the above commands. If those prints nothing, then empty string is assigned to PID variable. Thus the real process launched will be:

rsh unisxvr "PID=''; echo 'I will KILL:$PID'"

the commands executed in remote host are:

PID=''; echo 'I will KILL:'

I suggest to substitute double quotes for single quotes, but, be aware that you have other inner single quotes.

Re: rsh/sshWeird Behaviour

Alzhy — Fri, 16 Apr 2004 08:04:44 GMT

Man.. Thanks!

I should have caught this.. the rules of evaluation of UNIX commands...