argument count

javajynx · #1 (**permalink**) 08-24-2009

I'm writing a program that takes input from the user of a phone number or a name then either tells them if that entry doesn't exist in a text document or returns the entry if it does exist. But if they enter a name AND number it either returns the entry if it exists or adds it to the document.
To do this involves lots of if statements etcetc but to start I need to know how to tell the program if the user has only put in a number or name or if they've put in both name and number.

Long rant short is there a statement that tests if 1 or two arguments have been inputted?
would the following work?

Code:

if [ $1$2 ]
#test for number and name in document
elif [ $1 ] 
#test if its a valid number or name then test if it's in document

chompy · #2 (**permalink**) 08-24-2009

I would think the presence of a second input variable would be enough:

Code:

if [ -n $2 ]
#do this
else
#do this

of course you could always use a case statement, i guess it would depend on the number of variables you are testing for

javajynx · #3 (**permalink**) 08-24-2009

Thanks for your help.
Well the first variable is 1 argument or 2, then (if 1) number or name then validating the number or name then checking if the number/name is in the document (if 2) validating the number and name, checking if it's in the document and adding.
I was thinking having an outer if statment then cases in them to validate with if statements in those to check the document. Ah nesting, gotta love it.
With your [ -n $2 ] I'll be able to start it correctly.

Thanks very much ^_^

KenJackson · #4 (**permalink**) 08-25-2009

Maybe you want something like this:

Code:

#!/bin/sh
NAME= NUMBER=
while $# -gt 0; do
    if echo $1 | grep -qv '[^0-9-]'; then
        # $1 contains only digits and dashes
        test -n "$NUMBER"  &&  { echo "Too many numbers"; exit 1; }
        NUMBER=$1
    else
        test -n "$NAME"  &&  { echo "Too many names"; exit 1; }
        NAME="$1"
    fi
    shift
done

# Now process $NAME and $NUMBER if they aren't blank

I think grep -qv '[^0-9-]' is clever.
It quietly returns true if the value piped in does not contain any characters that are not digits or hyphens.
That is, if true, it only contains those characters.

-------------
Oops. I for forgot the brackets. The 'while' line should be:
while [ $# -gt 0 ]; do
or
while test $# -gt 0; do

javajynx · #5 (**permalink**) 08-25-2009

lol well my next question was how do I determine input is digits or not?
I tried the if echo $1 | grep -qv '[^0-9-]'
but it doesn't appear to accept it as false if I enter a name ie enter 12345678 and it does the number part enter bob and it says invalid number.

Also after I get that figured out how do I get the line from the document that contains the name or number ie entered "bob jones" and it was found in the document. It needs to echo that result
ie Bob Jones 12345567
is there a grep option that returns the line itself?

chompy · #6 (**permalink**) 08-25-2009

Have you thought of maybe adding an option to your script:

Code:

script.sh --number 123456789

Code:

script.sh --name "Jim Jones"

That way you would be able to determine what type of validation you should apply. Also you may want to try this regular expression to match the number:

Code:

[0-9-]+

It will match more than one instance, I think yours was stopping at the first instance the expression was satisfied.

KenJackson · #7 (**permalink**) 08-25-2009

Quote:

Originally Posted by javajynx

lol well my next question was how do I determine input is digits or not?
I tried the if echo $1 | grep -qv '[^0-9-]'
but it doesn't appear to accept it as false if I enter a name ie enter 12345678 and it does the number part enter bob and it says invalid number.

Try this from the command line:

Code:

echo 1234 | grep -qv '[^0-9-]'  &&  echo RIGHT
echo 12A34 | grep -qv '[^0-9-]'  &&  echo WRONG

Quote:

Originally Posted by javajynx

Also after I get that figured out how do I get the line from the document that contains the name or number ie entered "bob jones" and it was found in the document. It needs to echo that result
ie Bob Jones 12345567
is there a grep option that returns the line itself?

What's the format of your file? Maybe something as simple as this:

Code:

grep "$NAME" file.txt

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