Error handling in shell

[PeroMed]

Hey.

I have a shell script that first runs gdb debuger, executes commands
and writes results in a .txt files.

So I have my first shell file written like so:

gdb -x gdb_commands.sh a.out > text.txt

With objdump I got names of classes which
i want to print in text.txt. So i put Ptype before them and made gdb_commands.sh.

In my gdb_commands.sh I have:
break main
run
Ptype CClassA #a class retrieved from objdump that is going to be printed in text.txt
Ptype CClassB # another class...
Ptype CClassC
Ptype __gnu_cxx # class I got from objdump but gdb doesnt find it.
Ptype CClassD #another class i want

This is what my script does... it succesfully prints first 3 classes
but at __gnu_cxx it prints an error and stops gdb_commands.sh script.
It doesnt quit from gdb debuger it just exits the gdb_comands.sh script.

How can I make it, so it WON'T exit the script or how
can I skip classes that are not found?

I get this error for gdb_commands.sh:
"Error in sourced command file:
No symbol "_gnu_cxx" in current context"

Please help me I realy want to get this to work.

[wje_lf]

Enter the following line at the bash prompt, and all will be revealed.

man expect

If man pages are not installed on your system, google this:

man expect linux

[PeroMed]

TNx for the tip.

So with expect I can make a script that will execute commands and wont
be botherd by errors?

But I dont know how to write a expect script I didnt find any tutorials on it.

[wje_lf]

So with expect I can make a script that will execute commands and wont
be botherd by errors?

No, but you can build an expect script which sends a command to gdb for each class, and just blindly keeps going.

I dont know how to write a expect script I didnt find any tutorials on it.

google this:

expect tutorial

Actually, I thought of two other alternatives, if you decide not to use expect:

1. Loop through all your class names. For each one, build a file that looks like this:
   

   break main
   run
   Ptype single_class_name

   and run gdb against that command file. Just let the loop run, and it should blindly go through the good and the bad.
2. If you still want to run gdb just once, don't include any class names that begin with underscore ("_").

[PeroMed]

What do you mean loop through?

you mean i should write first script like this:

gdb -x commands1.sh a.out > text.txt
gdb -x commands2.sh a.out > text.txt
gdb -x commands3.sh a.out > text.txt
gdb -x commands4.sh a.out > text.txt
.
.
.

and then commands1.sh would be

break main
run
Ptype CClassA
quit

commands2.sh

break main
run
Ptype CClassB
quit

and so on....??

Well i did though of that and the problem is that when script in gdb stops
at Ptype __gnu_cxx it doesnt exit gdb and so you cant execute another
command in first script until gdb is closed.

[wje_lf]

the problem is that when script in gdb stops at Ptype __gnu_cxx it doesnt exit gdb

Enter the following line at the bash prompt.

man gdb

If man pages are not installed on your system, google this:

man gdb linux

Within the man page, look for the -batch option.

[PeroMed]

-batch did the trick thanks a lot.