Bash shell script: Str(007) to int(7),increment it(8) & convert back to string(008)

drwatson_droid · 12-01-2011, 09:26 AM

Hi,
I have the following requirement.

There will be following text/line in a file (eg: search-build.txt)
PRODUCT_VERSION="V:01.002.007.Build1234"

I need to update the incremental build number (eg here 007) every time I give a build through script. I am able to search the string and get the item.

Quote:

rexpression_sed='PRODUCT_VERSION=\"V:$[0-9]*$.$[0-9]*$.$[0-9]*$.Build$[0-9]*$\"'
var2=`grep -sn $rexpression_sed search-build.txt | sed -e 's/'$rexpression_sed'/\1\t\2\t\3\t\4/g'| cut -f 3`
echo $var2

Output
007

How to convert this to integer (7), add 1 to it (8) and again get back in the same form (008) in the easiest way? I will be using sed -i on the file, with this new string that can be used with RE for replacing that part!
Or
Is there any better method than above.

Thanks for any help.

MensaWater · 12-01-2011, 09:38 AM

If you add the following to the end of your script you'll get the increment:

Code:

calcval=$(expr $var2 + 1)
echo $calcval
newval="00$calcval"
echo $newval

You'd then have to plug $newval into the rest of the string.

drwatson_droid · 12-01-2011, 09:40 AM

Quote:

Originally Posted by MensaWater

If you add the following to the end of your script you'll get the increment:

Code:

calcval=$(expr $var2 + 1)
echo $calcval
newval="00$calcval"
echo $newval

You'd then have to plug $newval into the rest of the string.

thanks a lot

thesnow · 12-01-2011, 09:42 AM

Is the string always supposed to be 3 digits, or have 2 leading zeroes (would "10" be 010 or 0010)?

drwatson_droid · 12-01-2011, 10:24 AM

here is the final script

Quote:

newval=0
filename=search-build.txt
rexpression_sed='PRODUCT_VERSION=\"V:$[0-9]*$.$[0-9]*$.$[0-9]*$.Build$[0-9]*$\"'

incrementnum=`grep -sn $rexpression_sed $filename | sed -e 's/'$rexpression_sed'/\1\t\2\t\3\t\4/g'| cut -f 3`
echo "Current Incremental number is: " $incrementnum
if [ $incrementnum ]
then
calcval=$(expr $incrementnum + 1)
#echo $calcval
if [ $calcval -le 9 ];
then
newval="00$calcval"
elif [ $calcval -le 99 ];
then
newval="0$calcval"
else
newval="$calcval"
fi
echo "New Incremental number is: " $newval
rexpression_rep_final='PRODUCT_VERSION="V:\1.\2.'$newval'.Build\4"'
#replace with new number
sed -i 's/'$rexpression_sed'/'$rexpression_rep_final'/' $filename
fi

firstfire · 12-01-2011, 10:44 AM

Hi.

Use `printf' to pad your number with zeros.
For example:

Code:

$ printf "%0.3d\n" 15
015

'0.3d' means print an integer with minimum width of 3 digits, padding it with zeros if necessary. See `man printf' and `man 3 printf' for details.