topic Re: How can I reduce count value in shell scripting in Operating System - HP-UX

How can I reduce count value in shell scripting

Saraswathy_1 — Fri, 26 May 2006 06:15:12 GMT

I have set variable in script in between want to reduce the count by one.

Please advice.

Re: How can I reduce count value in shell scripting

Peter Godron — Fri, 26 May 2006 06:21:42 GMT

Hi,
man expr

a=10
a=`expr $a - 1`
echo $a
9

Re: How can I reduce count value in shell scripting

James R. Ferguson — Fri, 26 May 2006 06:26:43 GMT

Hi:

Using the shell's arithmetic:

# X=10;X=$((X - 1));echo ${X}

Regards!

...JRF...

Re: How can I reduce count value in shell scripting

Bill Hassell — Fri, 26 May 2006 06:27:14 GMT

Another way which is easier to read is:

let MYVAR=$MYVAR-1

You can use normal math symbols in the arithmetic let statement:

let MYVAR=$MYVAR*3
let MYVAR=$VAR2-$VAR3+1

Re: How can I reduce count value in shell scripting

Ninad_1 — Fri, 26 May 2006 07:02:03 GMT

There are several ways as mentioned above as well as

echo $MYVAR - 1 | bc

If you want to store in a variable
result=$(echo $MYVAR - 1 | bc)

Regards,
Ninad

Re: How can I reduce count value in shell scripting

Glen R. Bartlett — Fri, 26 May 2006 07:02:46 GMT

In the superior Scripting language of Perl :) you can use the same pre-fix and post-fix operators as C/C++.

a++; increase by 1
a--; decrease by 1

Re: How can I reduce count value in shell scripting

Peter Nikitka — Fri, 26 May 2006 07:10:37 GMT

Hi,

I'm missing this format:

typeset -i var=12
((var-=1))

print $var says 11

mfG Peter

Re: How can I reduce count value in shell scripting

Glen R. Bartlett — Fri, 26 May 2006 07:28:19 GMT

csh can also use the C type operators

--------------
#!/usr/bin/csh

@ a = 4
@ a--
echo "$a"
@ a += 2
echo "$a"
--------------
output:
3
5

Re: How can I reduce count value in shell scripting

Rodney Hills — Fri, 26 May 2006 09:35:05 GMT

You can say-

(( MYVAR=MYVAR - 1 ))
or equivalent
let "MYVAR=MYVAR - 1"

Note that you don't need $ in front of variables names since the shell is doing the arithmetic calculations.

HTH

-- Rod Hills

Re: How can I reduce count value in shell scripting

Saraswathy_1 — Fri, 26 May 2006 10:25:04 GMT

thanks