[surfnschultz]

How would I capture to compare the first number in a 3 or 4 digit string

I have set in the .profile a user stornum and they enter a port number
and I want to make sure the first digit of the 3 or 4 digit long numeric is equal to the stornum value

STORNUM="4"
portnum = 4321

I want to do this

if ($STRONUM -eq (1st digit of portnum))then
continue
else
exit
fi

thanks for any tips the race to solution is on.

[codejockey]

You don't mention what shell you're using, but I'll assume it's a Bourne-shell type (i.e., sh, bash, ksh) and not a C-shell type (csh, tcsh). If you know your portnumber will always be 4 digits, you can obtain the first digit by dividing by 1000; try:

portnum=7381
digit=`expr $portnum / 1000`
echo first digit is $digit

Also, you may be able to use an index/substring function (available in ksh and bash, I believe) to extract the first character of a string, which has the advantage of not needing to know the number of digits in the portnumber value. You can also determine the correct divisor to use by checking the length of the portnum value. You could code a more general solution something like this:

portnum=829
divisor=1000       # must be at least 10^((maximum length of portnum) - 1)
digit=0

while [ $digit -eq 0 ]
do
    digit=`expr $portnum / $divisor`

    if [ $digit -eq 0 ]
    then
        divisor=`expr $divisor / 10`
    fi
done
echo first digit is $digit

Hope this helps.

[Squashman]

firstdigit=`echo $portnum | cut -b1`
or
firstdigit=`echo $portnum | cut -c1`

[surfnschultz]

This is all in KSH, on a AIX system.

I am setting a value STORNUM in the .profile to be the store number the employee comes from. The first digit of the portnumber would be the store number.

at the prompt echo $STORNUM I get a number like 4

in my script if I put echo $STORNUM I get nothing.

I tried
echo `$STORNUM`
echo !$STORNUM
echo `STORNUM`

How do I echo the .profile value to the screen?

I also had a problem I was confused about If I write in my script
firstdig = `ceho $portnum | cut -b1`

I get an error saying cannot find firstdig???? How do create a variable to assign a value to in KSH?

anyway monday morning confusion.

Goal is to read STORNUM and compare to first digit then decide if number are equal to proceed if not exit

if [ `echo $portnum | cut -b1` -eq $STORNUM ] then
else
exit
fi

can't get STORNUM part to work?

Thanks for any help

[Squashman]

Originally Posted by surfnschultz

I also had a problem I was confused about If I write in my script
firstdig = `ceho $portnum | cut -b1`

I get an error saying cannot find firstdig???? How do create a variable to assign a value to in KSH?

Don't use spaces

[codejockey]

in my script if I put echo $STORNUM I get nothing.

I tried
echo `$STORNUM`
echo !$STORNUM
echo `STORNUM`

How do I echo the .profile value to the screen?

There are several things going on here:
(0) as the Squashman notes, there should be no spaces on either side of the equals sign in an assignment statement.

(1) different quotes mean different things to the shell. For example, single quotes mean (roughly) "take everything I typed literally" -- i.e., if you type asterisk (*), then the shell does NOT expand it; rm * is NOT the same as 'rm *'. The first attempts to remove all files in the current directory; the second attempts to remove a file named * in the current directory. Double quotes allow filename and globbing (wildcard) expansion, as well as environmental variable substitution. For example, rm "this is a test" attempts to remove a file named "this is a test" (without the quotes) in the current directory. The command: rm this is a test attempts to remove four files named this, is, a and test in the current directory. In this case, there would be no difference between the single and double-quote meaning, because the command contains no globbing, filename expansion or variable substitution. However, the command rm 'this is*' is not the same command as rm "this is*"; the first attempts to remove a file named "this is*" in the current directory, while the second attempts to remove all files that begin with the characters "this is" in the current directory.

(2) back-tics (accent grave -- i.e., `) execute what is contained between the back-tics as a command.

(3) the exclamation point is usually used as a shell escape from within a program (such as vi, for example) and often allows you to execute a command and capture the output. Note that you may need a space between the exclamation point and the command to be executed. However, if you code echo !$STORNUM, the shell will first perform variable substitution and replace $STORNUM with its value (4, in this case?) and then display !4 to the screen.

Here's how I suspect the shell interpreted your attempts:

echo `$STORNUM`      -> displayed $STORNUM (literally) on the screen
echo !$STORNUM        -> displayed ! followed by the value of STORNUM on the
                                         screen
echo `STORNUM`        -> shell attempts to execute a command named STORNUM 
                                         and echo the results.  Since there is likely no command 
                                         named STORNUM, the shell produces an error.

Quoting can be very confusing (and that's only the beginning! ). Hope this helps.