bash scripting..simple question

bash scripting..simple question

[urgrue]

is there a way, in a bash script, to do something like:
execute "this_command these_params" 
--if-its-not-done-in-600-seconds-then-kill-it-and-return-an-error-code

situation is, i have a simple script that logs into remote boxes, and 
does some checks.
it first pings each box to see if the route is up, if that fails it 
wont even try to log in.
but sometimes, a box can be pinged but not logged into, for various 
reasons.
in these cases, the ssh login attempt seems to just sit there and 
doesnt timeout, and the whole script hangs, waiting until ssh exits. 
which i have observed to take at times HOURS, at times it _never_ exits.

any suggestions?

Re: bash scripting..simple question

[Carl]

At 12:16 13/09/2002 +0300, urgrue wrote:
>is there a way, in a bash script, to do something like:
>execute "this_command these_params" 
>--if-its-not-done-in-600-seconds-then-kill-it-and-return-an-error-code
>
>situation is, i have a simple script that logs into remote boxes, and 
>does some checks.
>it first pings each box to see if the route is up, if that fails it 
>wont even try to log in.
>but sometimes, a box can be pinged but not logged into, for various 
>reasons.
>in these cases, the ssh login attempt seems to just sit there and 
>doesnt timeout, and the whole script hangs, waiting until ssh exits. 
>which i have observed to take at times HOURS, at times it _never_ exits.
>
>any suggestions?

I can't give you a quick answer, but i use "expect" to do anything interactive
that i don't want to do manually. Stuff like setting passwords on multiple hosts
and checking disk space etc...

I read the blurb on expect and was sceptical on how important it can be
to a sys-admin but i'm now hooked and it is my first port of call for doing
routine things many times.

If you know tcl it will be a breeze and even if you don't it is fairly straight forward.

See http://expect.nist.gov for info on expect.

--
Carl

Re: bash scripting..simple question

[Michael Salmon]

On Friday, September 13, 2002 12:16:11 PM +0300 urgrue <urgrue@tumsan.fi> 
wrote:
+------
| is there a way, in a bash script, to do something like:
| execute "this_command these_params"
| --if-its-not-done-in-600-seconds-then-kill-it-and-return-an-error-code
|
| situation is, i have a simple script that logs into remote boxes, and
| does some checks.
| it first pings each box to see if the route is up, if that fails it
| wont even try to log in.
| but sometimes, a box can be pinged but not logged into, for various
| reasons.
| in these cases, the ssh login attempt seems to just sit there and
| doesnt timeout, and the whole script hangs, waiting until ssh exits.
| which i have observed to take at times HOURS, at times it _never_ exits.
|
| any suggestions?
+-----X8

It is a little tricky, you need to start the first command in the 
background and then sleep and kill that job if it is still running. Here is 
an example from a Bourbe shell script:

    rsh -n $gw test -x $cmd \&\& $cmd ${1+"$@"} > $tmp &
    pid=$!
    # timeout function
    (
        sleep 45
        if kill -0 $pid > /dev/null 2>&1
        then
            kill -TERM $pid
        fi
    ) &
    wait $pid

/Michael
--
This space intentionally left non-blank.

Re: bash scripting..simple question

[grottoBoy rant]

sleep will do what you want, i think.

I'm slow to give you the code, but the thought process is:
sleep 600 seconds
grep output from ps aux for the ssh login attempt maybe, if it hasn't exited 
then kill the process and continue running the script, maybe?

your earlier code will have to make sure that ssh process exits properly on 
successful completion...




----Original Message Follows----


is there a way, in a bash script, to do something like:
execute "this_command these_params"
--if-its-not-done-in-600-seconds-then-kill-it-and-return-an-error-code

situation is, i have a simple script that logs into remote boxes, and
does some checks.
it first pings each box to see if the route is up, if that fails it
wont even try to log in.
but sometimes, a box can be pinged but not logged into, for various
reasons.
in these cases, the ssh login attempt seems to just sit there and
doesnt timeout, and the whole script hangs, waiting until ssh exits.
which i have observed to take at times HOURS, at times it _never_ exits.

any suggestions?

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Re: bash scripting..simple question

[Glynn Clements]

urgrue wrote:

> is there a way, in a bash script, to do something like:
> execute "this_command these_params" 
> --if-its-not-done-in-600-seconds-then-kill-it-and-return-an-error-code

The "netpipes" package includes the "timelimit" command, which does
exactly this:

TIMELIMIT(1)                                         TIMELIMIT(1)


NAME
       timelimit  -  spawn a subprocess and if the child does not
       finish within the time limit  either  kill  it,  or  exit,
       leaving the child in the background.

SYNOPSIS
       timelimit [ -v ] [ -nokill ] time command args

-- 
Glynn Clements <glynn.clements@virgin.net>