Shell Programming and Scripting

I'm writing this script in Korn Shell, on AIX. The script will print a log file, and it needs to decide what region it's in before printing.

( the output of db2 "get instance" is either
"The current database manager instance is: db2q" or
"The current database manager instance is: db2u")

I have tried this, also an if statement, but I havent' got it to work yet, any ideas?

thanks
JP

echo "enter log number"$
read slog$
$
db2 "get instance" > reg$$$
grep "u$" reg$$ > regfile$
if [ -s regfile ]; then$
qu=u$
fi$
if [ -z regfile ]; then$
qu=q$
fi$
case $qu in $
u)$
cd /dir1/db2u/apps/log; ls|grep $slog > newlog; cat newlog|xargs cat $
$
rm newlog ;;$
q)$
cd /dir1/db2q/apps/log; ls|grep $slog > snewlog; cat snewlog|xargs cat$
rm snewlog ;;$
$
*) echo "bleh!" ;;$
esac$
$
rm reg$$; rm regfile$

You will need to double check the syntax, but you might try something like this....

echo "enter log number"
read slog
db2inst=$(db2 "get instance") #cmd sub in ksh
if [ $db2inst = db2u ]; then
od /dir.../log && ls|grep $slog > newlog; cat..
rm newlog
else
od /dir.../log && ls|grep $slog > ...; cat ...rm snewlog
####

Just ideas. The "&&" causes the second command to only run if the first is successfull.

I'm just writing this out off the top of my head, so it may not be correct, but try something like this:

Code:

#!/usr/bin/ksh

echo "Enter the log number: \c"
read slog
if [ -z "$slog" ]; then echo "No number entered."; exit 1; fi

echo "Do you want to [V]iew, or [P]rint the log? \c"
read v_p
case $v_p in
v|V) command="more" ;;
p|P) command="lp" ;;
*) echo "Not a valid action. Exiting."; exit 1 ;;
esac

db_tmp=$(db2 "get instance")
if [ -z "$db_tmp" ]; then echo "Error getting db name."; exit 1; fi
db_name=${db_tmp##*:}

cd /dir1/${db_name}/apps/log
cat *${slog}* 2>/dev/null || echo "Files with log number $slog not found" | ${command}

I *think* this should handle a similar job, although, once again, it hasn't been tested.
You'll notice a wierd line:
db_name=${db_tmp##*:}
That should drop anything before the colon... good ol' ksh...

Hope this helps...

thanks everyone, I took a piece of this and that, and ended up with a working script:


db2 "get instance" > /tmp/answer$$
grep db2q /tmp/answer$$ 1> /dev/null
if [ "$?" = 0 ]; then
cd /top/db2q/apps/log
else
cd /top/db2u/apps/log
fi

cat *$slog*
rm /tmp/answer$$


is there a more elegant way to test for a 0 value exit status?

You could save yourself a few processes by simply grabbing those lines that I used:

db_name=$(db2 "get instance")
cd /top/${db_name##*:}/apps/log
cat *${slog}*

Faster, more concise, and no "if" statements, nor a disk write and a grep. If you're going to use the Korn shell, why not use some of the builtin features to make your life easier, right?

yes, your code is better, but my system didn't like the substitution in the path, cd /top/${db_name##*:}/apps/log. The system is AIX, and I am forced to use the Korn shell, that's the only one that will work, I'd like to take more advantage of it's built in features.

thanks again

Really? Hmm, well, perhaps you could do it a similar way:

db_tmp=`db2 "get instance"`
db_name=`echo $db_tmp | awk -F": " '{print $2}'`

Then, either do this:
cd /top/$db_name/apps/log/

or this, if the above doesn't work:

case $db_name in
db2q) cd /top/db2q/apps/log/ ;;
db2u) cd /top/db2u/apps/log/ ;;
*) echo "Eek." ;;
esac

I'm not saying that you're doing it wrong - I guess I just feel uneasy with grepping a string out of a file... I usually try to touch the disk as little as possible in a small script.

Hmm, what do you think about this:

db2 "get instance" | grep "db2q" >/dev/null 2>&1
case $? in
0) cd /top/db2q/apps/log ;;
1) cd /top/db2u/apps/log ;;
*) echo "This should never happen." ;;
esac

That way is very similar to how your are doing it now, and I find case statements a little cleaner than if statements, but that's just my opinion.

Well, I hope this is helping at least a little...

It just goes to show how many ways there are to accomplish a task in Unix!