topic Re: How do you capture all terminal output resulting from running a script? in Operating System - HP-UX

How do you capture all terminal output resulting from running a script?

Kurt Renner — Thu, 23 May 2002 12:44:57 GMT

I am developing a script which will take our admins through the entire process of securing a HP-UX machine according to our corporate stds. I want a log file of all the activity performed within this script that can be used for later review in case there were problem areas in configuring the system.

One way I know I could do this is to use "tee" to write both to the terminal and to a log file. However, the scripting style I want to use is to call functions within an "if" statement. The functions will return 0 if successful, and non-zero if it is unsuccessful... similar to the following code.

if SomeFunction; then
State=/bin/true
else
State=/bin/false
fi

If I were to include a "| tee -a ${OutputFile}", it will skew the return code value of the function, and will always be true if the "tee" command is successful.

I could use tee in a pipeline when the script is initiated. I could also use the "script" command to capture it as well, but then every user would have to remember to invoke the script in one of these 2 ways... which wouldn't happen.

I tried putting the "script" command within the script, but as the man page says, I just get a spawned shell, and the script then proceeds after I exit the spawned shell... not capturing the output as I intend.

A good example of what I am trying to accomplish is the way the swintall command operates in non-interactive mode. All the terminal I/O is displayed to the user, and also captured in a file in the /var/adm/sw/ directory.

I'm looking to direct STDERR and STDOUT for the entire script, not individual commands, and to somehow do it within the script itself.

Any ideas would be appreciated.

Re: How do you capture all terminal output resulting from running a script?

Craig Rants — Thu, 23 May 2002 12:47:37 GMT

This may be what your looking for.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x6ac253921f1ad5118fef0090279cd0f9,00.html

GL,
C

Re: How do you capture all terminal output resulting from running a script?

Pete Randall — Thu, 23 May 2002 12:48:09 GMT

Put a wrapper around the script - another script that invokes your original with stderr and stdout redirected.

Pete

Re: How do you capture all terminal output resulting from running a script?

harry d brown jr — Thu, 23 May 2002 12:52:16 GMT

Before you start the "secure" process, type in "script /tmp/filename", then proceed to do your magic. If you use Exceed, you can do the same by "ctrl-leftmousebutton" then select "log to file".

live free or die
harry

Re: How do you capture all terminal output resulting from running a script?

Robert Gamble — Thu, 23 May 2002 12:53:36 GMT

Here is an approach you might not have expected in this forum:

Try using a video/screen capture device using an xterm. You could voice over with the 'why', while the trainee see the commands being entered.

I know it seems a bit hollywood, but I've used many such training materials, and the trainees really benefit from the commentary and the examples.

Good Luck.

Re: How do you capture all terminal output resulting from running a script?

Pete Randall — Thu, 23 May 2002 12:55:25 GMT

Disregard previous response - after I thought about it for a minute, I realized that isn't going to do anything for you. Oh well.

Pete

Re: How do you capture all terminal output resulting from running a script?

Sanjay_6 — Thu, 23 May 2002 12:56:21 GMT

Hi Kurt,

I think you are trying to capture the std output and the std err that gets displayed on the terminal when the script is run. Try this,

sh script >script.run.log 2>&1
or
./script >script.run.log 2>&1

Hope this helps.

regds

Re: How do you capture all terminal output resulting from running a script?

Bill Hassell — Thu, 23 May 2002 13:01:58 GMT

Probably the easiest way is to use script tracing (set -x or run the script as: sh -x script_name) and redirect STDERR to a file. Unfortunately, the default action for function calls is to turn off set -x so it would have to appear in every function too.

If you don't want all the trace statements, then you'll be best off writing a separate function for displaying all messages. So instead of writing:

echo "Enter new data: \c"

you would use (assumes $LOGFILE has already been defined):

LogWrite "Enter new data: \c"

and write a function like:

function LogWrite
{
print "$@" | tee -a $LOGFILE
}

And to capture non-zero exit codes seen by the shell put this trap statement at the beginning:

trap 'ErrWrite $0: A non-zero returncode occurred at line $LINENO' ERR

This trap statement will add the name of the script and the line number where any error return was detected. You may want to tee the error output into a different file such as $ERRLOG. The function ErrWrite would be:

function ErrWrite
{
print "$@" | tee -a $ERRLOG
}

For calls to processes that may return STDERR, you'll have to add: 2>>$LOGFILE (or 2>>$ERRLOG) to the end of each process call.

Re: How do you capture all terminal output resulting from running a script?

Steve Steel — Thu, 23 May 2002 13:03:31 GMT

Hi

As shown

script /tmp/file

Prompt will return

script

At end of script
exit

Prompt will return

All output to the screen is in /tmp/file

To debug the script if needed put set -x as
the first non comment line and all commands are also echoed as they are executed

steve steel

Re: How do you capture all terminal output resulting from running a script?

Kurt Renner — Thu, 23 May 2002 17:31:56 GMT

Thanks a bunch for all the suggestions. I really like the quick responses I get when posting a question in this forum.

While I didn't use any of the ideas exclusively, I got a different idea from them, and thought I would share my solution:

Here's the code I put in the first part of the Main section of my script after all my function declarations:

: ${ScriptLog:="/tmp/${0##*/}.log"}; export ScriptLog
: ${FirstTimeThru:=/bin/true}; export FirstTimeThru

if ${FirstTimeThru}; then
test -f "${ScriptLog} && /usr/bin/mv ${ScriptLog} ${ScriptLog}.old || > ${ScriptLog}
export FirstTimeThru="/bin/false"
${0} $@ 2>&1 | tee -a ${ScriptLog}
else
exit $?
fi

I've tested this logic, and it gives me exactly what I was looking for. Thanks for all the suggestions!!!

Re: How do you capture all terminal output resulting from running a script?

Pete Randall — Thu, 23 May 2002 17:37:01 GMT

Kurt,

Have you checked HP-UX Bastille? It's a tool to help you secure your systems. See http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xc2d291ccb36bd611abdb0090277a778c,00.html

Good luck,
Pete

Re: How do you capture all terminal output resulting from running a script?

Kurt Renner — Thu, 23 May 2002 18:08:43 GMT

It seems I had heard about it many months ago, and had not gotten a chance to do anything with it, and in the meantime had completely forgotten about it. I sent off for it. Hopefully I will get it today yet, and take it for a spin.

Thanks for the tip. It is much appreciated!

Re: How do you capture all terminal output resulting from running a script?

Pete Randall — Thu, 23 May 2002 18:11:20 GMT

You're very welcome for the tip. And thanks for the new hat. You pushed me over the edge - thanks.

Pete

Re: How do you capture all terminal output resulting from running a script?

Kurt Renner — Thu, 23 May 2002 18:18:03 GMT

No problem. If it's as good as it sounds from the other posting, it will have saved me a LOT of work. Have another hat!