check whether the value changes or not!

Shell Programming and Scripting
1

HI all,

I need help in writing a shell script for the following logic

I have a file abc.txt and it contains a number x. The number in the file abc.txt changes every day. I need to develop a shell script which on every run checks the number in the file and increments a variable by 1 if a new number is found( if the number doesnt change the variable will not increment by 1).

Can any one help me out in this. Thanks!

2

How often do you want to run the check? You could either use a corntab script and a temp file or leave a script running a looping the check....

3

Thanks for the response! The script is run manually by me only to check for the changed value

4

I ain't sure what you really want, but try this:

NUMBER=`cat abc.txt`

if [ ! -f ~/tmp.file ]; then
    touch ~/tmp.file
    echo "$NUMBER:1" >> ~/tmp.file
    echo "First number saved, variable set to 1"
    exit
else
    OLDNUMBER=`cat ~/tmp.file | awk -F":" '{print $1}'`
    VARIABLE=`cat ~/tmp.file | awk -F":" '{print $2}'`
    if [ "$OLDNUMBER" != "$NUMBER" ]; then
        VARIABLE2=$(( $VARIABLE + 1 ))
        cat /dev/null > ~/tmp.file
        echo "$NUMBER:$VARIABLE2" >> ~/tmp.file
        echo "New variable: $VARIABLE2"
    else
        echo "Number hasn't changed, variable stays $VARIABLE"
    fi
fi
5

Tech one! Thanks a million, that is what i needed!

Once again Thanks a lot!