Shell Programming and Scripting

Hi,

I am running a bteq command in UNIX and I want bteq output to be displayed on stdout and also be logged to a file using unix 'tee' command. Also I intend to check the bteq return code and take necessary action. Here is the code snippet -

*****************************************************

Code:

bteq << EOF | tee bteq_log_file
.logon td1/user1,passwd;
select count(*) from table;
.IF errorcode <> 0 .GOTO ERROR;

.LABEL ERROR
.QUIT 99
.LOGOFF
.QUIT
EOF

RETURN_CODE=$?

if [ $RETURN_CODE -ne 0 ]
then
exit $RETURN_CODE
fi

*****************************************************

When bteq throws an error the "if" logic is supposed to evaluate to true and the program should exit. However, the return code check below is not working because it is in effect evaluating the return code of the 'tee' command (which is executed after bteq) and not evaluating the return code of the bteq, which executes before 'tee'. So the return code check always evaluates to 'true' even when the bteq command returns a non-zero exit status.

Is there any way to circumvent this problem ? I want to display the output of bteq on stdout and redirect to a file and also check the return code of bteq (and not that of tee).

Please advise.

Thanks

You're lucky if you're using a recent bash - it provides an array with all the exit codes of a pipe. man bash:

In all shells you can do

Code:

{
bteq << EOF
.logon td1/user1,passwd;
select count(*) from table;
.IF errorcode <> 0 .GOTO ERROR;

.LABEL ERROR
.QUIT 99
.LOGOFF
.QUIT
EOF

RETURN_CODE=$?

if [ $RETURN_CODE -ne 0 ]
then
exit $RETURN_CODE
fi
} | tee bteq_log_file

It relies on proper SIGPIPE handling. (I have seen an issue with applications that set a bad signal mask and then spawn a shell where SIGPIPE cannot be handled.)
Or try the safe&simple

Code:

logfile=bteq_log_file
bteq << EOF >$logfile
.logon td1/user1,passwd;
select count(*) from table;
.IF errorcode <> 0 .GOTO ERROR;

.LABEL ERROR
.QUIT 99
.LOGOFF
.QUIT
EOF

RETURN_CODE=$?

cat $logfile

if [ $RETURN_CODE -ne 0 ]
then
exit $RETURN_CODE
fi

@MadeInGermany - Thanks for your suggestion. The 2nd solution is simple and effective :-) I will pursue the same...

However, one question - Why doesn't redirecting the output to a file not alter the return code of bteq ? Anyway, redirection is also an "operation" which would have its own return code (i think) to indicate success or failure ??

Thanks much !

Good question. Redirection is not a command in itself, but is part of the command and is used to open/close files.

Code:

bteq << EOF >$logfile

is equivalent to

Code:

>$logfile bteq << EOF

or even

Code:

<<EOF >$logfile bteq

If a redirection fails, then the command as a whole fails