Shell Programming and Scripting

I got rather bored so i decided to create a script that creates a countdown, and shows hours:minutes:seconds till that time.
It works fine until the seconds of the actual time reaches 8, then it tries to use it to work out the difference as in "SECONDDIFF=$[SECOND-ALARMSECOND]"
Here's my code where I get the problem :

Code:

ALARMHOUR=`echo "$ALARMTIME" | cut -d : -f 1 `
ALARMMINUTE=`echo "$ALARMTIME" | cut -d : -f 2 `
ALARMSECOND=`echo "$ALARMTIME" | cut -d : -f 3 `
...

TIME=`date "+%H:%M:%S"`

HOUR=`echo "$TIME" | cut -d : -f 1 `
MINUTE=`echo "$TIME" | cut -d : -f 2 `
SECOND=`echo "$TIME" | cut -d : -f 3 `

SECONDDIFF=$[SECOND-ALARMSECOND]
SECONDDIFF=$[60-SECONDDIFF]

The line i get the error at is SECONDDIFF=$[SECOND-ALARMSECOND] and
The error i'm getting is :
/bin/TermTime (unstable): line 35: 08: value too great for base (error token is "08")
I simply cannot even guess how to fix this, i simply have no idea, Help me please someone?

What shell are you using?

There's several ways better than running cut 3 times to process one line.

A way that'll work in all shells:

Code:

VAR="12:34:56"

OLDIFS="$IFS"
IFS=":";   set -- $VAR;   IFS="$OLDIFS"
HH=$1
MM=$2
SS=$3

This will overwrite your $1,$2,$3 parameters.

Other ways may be available depending what your shell is.

I'm using BASH... On a mac running lion if that helps

It does.

Try X=$((Y-Z)) instead of X=$[Y-Z].

BASH can also do this:

Code:

read A B C <<<$(date +"%H %M %S")

Hundreds of times faster than running three external utilities to process one line.

or:

Code:

#!/bin/ksh
eval "$( date '+ h=%H =%H m=%M s=%S' )"
echo $h $m $s

Thank you for the help speeding up the execution, however I only posted for the problem i was getting... Any idea what it is and how to sort it out?

Check my last post. I answer your question directly and tell you how to fix it.