topic Re: shell script help in Operating System - HP-UX

shell script help

1a — Tue, 05 Jul 2011 10:21:55 GMT

i want to compare two values in shell script .

example-

ca=50

pa=45

if [ $ca -gt $pa ]

i need output greater value . how to print the vaule after the if statement.

Re: shell script help

Hakki Aydin Ucar — Tue, 05 Jul 2011 10:46:24 GMT

if [ $ca -gt $pa ]
then
echo $ca
fi

Re: shell script help

V. Nyga — Tue, 05 Jul 2011 11:48:29 GMT

if [ $ca -gt $pa ]
then
echo $ca
elif [ $pa -gt $ca ]

then
echo $pa
else
echo "They are equal"
fi

(Sorry Hakki) :-)

Re: shell script help

Hakki Aydin Ucar — Tue, 05 Jul 2011 11:49:21 GMT

Danke ! :smileyvery-happy:

I missed the half part of code..

Re: shell script help

James R. Ferguson — Tue, 05 Jul 2011 11:58:40 GMT

Hi:

Since you only want the greater value, or if they are equal, merely that value, you could use:

# [ ${ca} -gt ${pa} ] && echo ${ca} || echo ${pa}

Regards!

...JRF...

Re: shell script help

Dennis Handly — Tue, 05 Jul 2011 15:18:50 GMT

If you are using a real shell you can use C style expressions:

if (( ca > pa )); then

echo $ca

else

echo $pa

This prints the maximum of the two.

Re: shell script help

1a — Wed, 06 Jul 2011 14:25:06 GMT

hi every one thanks for you reply

Dennis,

i user your script , it working fine . please tell how to print the greater value in one text file

Re: shell script help

1a — Wed, 06 Jul 2011 14:27:41 GMT

Sorry dennis,

i use your script , it is working fine. please tell how to print the greater value in one text file

because i need output value through mail, so i plan to send mailx command.

Re: shell script help

Tom Maloy — Wed, 06 Jul 2011 16:19:21 GMT

Starting with Dennis' script, and noting that nothing will print if the values are equal, this might work:

if (( ca > pa )); then

echo $ca

else

echo $pa

fi > max.txt

mailx -s "max values" mail_address_here < max.txt

Re: shell script help

Dennis Handly — Wed, 06 Jul 2011 16:28:57 GMT

And if you don't plan to send much text to your message:

if (( ca > pa )); then

echo $ca

else

echo $pa

fi | mailx -s "max values" mail_address_here

>noting that nothing will print if the values are equal:

The above fragment always prints a value.

Re: shell script help

James R. Ferguson — Wed, 06 Jul 2011 19:17:23 GMT

Hi:

No matter which script you like ( and we'll use Dennis's since you reference his ), consider learning a Unix philosophy that says do-one-thing-and-do-it-well.

The whole script could be:

# cat mymax

#/usr/bin/sh

typeset ca=$1

typeset pa=$2

if (( ca > pa )); then

echo $ca

else

echo $pa

...which then could be run to output to your terminal:

# ./mymax 100 99

100

...or to a file:

# ./mymax 100 99 > myoutput

...or to email:

# ./mymax 100 99 | mailx -s "Max Value" mymailaddress

The point is to allow the user to determine where he/she wants the output to appear rather than hard-coding that assumption into your script.

Regards!

...JRF...

Re: shell script help

1a — Thu, 07 Jul 2011 04:17:53 GMT

Hi dennis,

if the values are equal , how to print the value.

Re: shell script help

1a — Thu, 07 Jul 2011 05:43:10 GMT

hi james R.

thanks for your reply. i want to learn shell script .please send any pdf document or ppt

Re: shell script help

Dennis Handly — Thu, 07 Jul 2011 06:07:24 GMT

>if the values are equal, how to print the value.

Is this a new question?

Otherwise my script fragment will print the maximum of the two and always prints, even if equal.

If you only want to print if they are equal:

if (( ca == pa )); then

echo $ca

Re: shell script help

James R. Ferguson — Thu, 07 Jul 2011 14:05:23 GMT

@1a wrote:

thanks for your reply. i want to learn shell script .please send any pdf document or ppt

I used to recommend the "HP-UX Shell User's Guide" which was a nice overview of the various shells. With the advent of the "improved" (NOT!) HP websites, this doesn't appear to be available anymore.

Regardless, there are any number of good books on shell scripting. Find one for beginners and begin. I urge you to confine your initial learning to the Korn ('ksh') or Bash ('bash') shell rather than the dysfunctional C shell. In HP-UX, the default shell is simply called 'sh' and is a Korn variant. Bash can also be installed on HP-UX though it is usually the standard for most Linux distributions.

Part of learning to write code (in any language) is *writing* and *reading*. A very good collection of shell scripts is available here:

http://www.shelldorado.com/

Regards!

...JRF...

Re: shell script help

Stephan. — Sat, 09 Jul 2011 07:13:48 GMT

I only have a pretty old copy of the shell user's guide but it's still a pretty good one.

Find it attached.

hth,

Stephan