signal error

lipun4u · 06-16-2010, 01:23 PM

#!/bin/sh

trap "echo Haha" SIGUSER1
echo "asit"
count=1
while [ $count -le 10 ]
do
echo "Loop #$count"
sleep 10
count=$[ $count + 1 ]
done
echo "This is the end"

plz check out...why this is showing following error ???
trap: 3: SIGUSER1: bad trap

alunduil · 06-16-2010, 01:39 PM

The second argument to trap needs to be an executable that will be executed on logout. Perhaps, the following will work: `trap $(echo Haha) SIGUSER1.

Regards,

Alunduil

konsolebox · 06-16-2010, 02:05 PM

You can't trap multi-token simple commands. You need to encapsulate them inside functions like:

Code:

haha() {
    echo Haha
}

trap haha SIGUSER1
...

lipun4u · 06-17-2010, 02:15 PM

does unix and linux vary in the way they handle signal ???

konsolebox · 06-20-2010, 10:01 PM

Quote:

Originally Posted by lipun4u

does unix and linux vary in the way they handle signal ???

Inter-process communication (IPC) of Linux was based from UNIX (read "The Design of the UNIX Operating System" which Linux was based) so probably it's the same although I'm still not certain. Still it's best to just try it with other systems anyway.