Looping a ksh script

[Christopher Hildrum_1]

I know this will be easy for some of you ...

I have created a login termination script. I want to continue looping this script until I type q on the command line. I need to run it manually (policy) and check for login/ids in my script.

How can I create a basic loop to start and return to the beginning after completing each process.

More explaination:

while (I input something)
run my script
go back to top until I input "q".

Thanks in advance,

Chris

[Hai Nguyen_1]

Chris,

try this:

while true;
do
your commands here;
done;

Use Control+C to stop the loop.

Hai

[Marco Santerre]

Why don't you do something like this :

while [ 1 ]
do

run script
echo "Quit (q) ? "
read key_stroke

if [ "$key_stroke" = "q" ]
then break
fi
done

[James R. Ferguson]

Hi CHris:

Here's one way:

#!/usr/bin/sh
typeset -l REPLY
while [ "${REPLY}" != q ]
do
echo "Choose your poison..."
read REPLY
[ "${REPLY}" = q ] && continue
echo "looping"
done
echo "exiting now"
exit 0

Note the use of the 'typeset' to declare that automatic translation to lowercase characters should be made for any REPLY. This makes' testing for responses short and easy -- no convern for uppercase versus lowercase or mixed case.

Regards!

...JRF...

[Michael Steele_2 · Accepted solution]

FILE=/etc/passwd
TEST=103
LOGFILE=$HOME/logfile
>$LOGFILE

cat $FILE | while read a b c d e f g
do
if [[ $d=$TEST ]]
then
break
elseif
continue
fi
done >> $LOGFILE

[Christopher Hildrum_1]

Thanks you all -

I like the different takes on each issue - I will probably use them all in one way or another down the road.

michael - I was looking for the "continue"!.

How simple!

Thanks -
Chris

[twang]

You may take a look at this loop:

while : ;
do
echo "Display Menu"
resp=*
read resp
case $resp in
[M,m])
cmd
;;

[q,Q])
echo "$program: $exit_code"
exit 0
;;

*)
echo Invalid Responce
sleep 1
;;
esac
done

[Christopher Hildrum_1]

Let me add something else to this one for you:

I am entering a UID and searching a local file that contains all UIDs,etc:

Top part of script:
#########################
print -n 'User ID to lock ?\n'
read USER
if [[ `/software/master/find_uid.sh "$USER:"` = "" ]];then
print "No accounts available"
return
else
continue
fi
#################
How do I return to re-input a new UID if there is no information in my file?


Thanks again !
Chris

[Hai Nguyen_1]

Chris,

"continue" will do it!

Hai

[Christopher Hildrum_1]

Hai -

continue continues moving through the script - I need to replace the "return" with something that will "start the script over or re-enter the UID.

Chris

[Hai Nguyen_1]

Chris,

I modified your part to become:

while true;
do
print -n 'User ID to lock ?\n'
read USER
if [[ `/software/master/find_uid.sh "$USER:"` = "" ]];then
print "No accounts available"
continue
else
break
fi
done

[twang]

RETURN=""
while [ test $RETURN != "yes" ]
do
echo "Display Menu"
resp=*
read resp
case $resp in
[R,r])
run cmd....
exit_code=$?
;;
[C,c])
RETURN="yes"
;;

[q,Q])
echo "$program: $exit_code"
exit 0
;;

*)
echo Invalid Responce
sleep 1
;;
esac
done

I have revised the above code, it continues if "C" or "c" is entered.

[Christopher Hildrum_1]

Thanks Hai and all - I think I got it now !

Chris

[vasundhara]

Hi Chris,

Just an addition.

"continue" is very useful only in loop controls. i.e. when you are using while, for etc... If the statement "continue" is not in a loop, it is equal to not writing the statement itself.

Do not use "continue" frequently in one script as the performance comes down. I read it in some book that in big loops if you are using continue, the internal stack needs to be loaded many times and so the speed comes down. For small loops, you can use it.

Thanks and Regards
VJ.