Test If Command Line Parameter Not Passed 2

[Michael42]

Hello,

In a UNIX Bourne shell scipt how can I test if a command line parameter is not passed?

Example (with param): ./myscript "Albatross"
Example (without param): ./myscript

Thanks,

Michael42

 

[olded]

Check the number of aguments:

#!/bin/sh

if [ $# -eq 0 ]
then
   echo "argument not passed"
fi

 

[feherke]

Hi

No idea in [tt]sh[/tt], but try the [tt]bash[/tt] way :

# Expands to the number of positional parameters in decimal.

test $# -eq 0 && echo "I got no arguments"

Feherke.

http://rootshell.be/~feherke/

 

[PHV]

If you want to provide a default value:
myArg=${1-Albatross}

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[feherke]

Hi

Or do you mean a specific parameter was not passed ? Then you need to check the arguments one by one. ( Or someone will tell you a more simple solution using [tt]getopts[/tt]. )

Feherke.

http://rootshell.be/~feherke/

 

[Michael42]

Guys,

This is very useful: if [ $# -eq 0 ]

If I could take this a little deeper. How can i test for the 2nd and 3rd command line parameters?

Example: ./myscript one two three


Thanks again,

Michael42

 

[feherke]

Hi

test $# -lt 3 && echo "Got less then 3 arguments, so no 3rd argument"

Feherke.

http://rootshell.be/~feherke/

 

[Michael42]

Oop that was a bit incomplete - sorry.

More clearly, what is the best way to test if $2 and $3 have no value.

Thanks,

Michael



Thanks,

Michael42

 

[PHV]

[ -z "$2" ] && echo "No 2nd arg !"

Anyway:
man test
man sh

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[Michael42]

Guys,

Thanks again for your advice. Thanks to your help I have been able to cut the number of coding lines in half.

Regards,

Michael42