bash script check input argument

Question

Today, I have to check the existence and the number of input arguments. I have the following script:

#!/bin/bash

echo "*** Test ***"
echo
echo $#
echo $*

function test1(){
   echo "test"
}

function GetTime()
{
   echo "Get Time function"
   if [ "$#" -ne 1 ]; then
       echo "Illegal number of parameters"
   else
       test1
   fi
}

if [ "$#" -ne 1 ]; then
    echo "Illegal number of parameters"
else
    test1
    GetTime  
fi

When I enter ./test.sh GetTime I get

*** Test ***

1
GetTime
test
Get Time function
Illegal number of parameters

I do not understand why the behavior is different between the first condition and the one contains within the GetTime() function. Somebody could help me ?

Thank in advance

Have you missed posting some of your script? How is GetTime() even being called? — GreenAsJade
– GreenAsJade, Commented Nov 17, 2014 at 15:03
Since when are bash functions defined using a function keyword? — Géza Török
– Géza Török, Commented Nov 17, 2014 at 16:16

nu11p01n73R · Accepted Answer · 2014-11-17 15:11:23Z

3

It is different because $# in first if refer to the number of arguments to the shell script. Where as the $# in second indicates the number of argument to GetTime function

To understand more I have modified the GetTime function as

#!/bin/bash

echo "*** Test ***"
echo
echo $#
echo $*

function test1(){
   echo "test"
}

if [ "$#" -ne 1 ]; then
    echo "Illegal number of parameters"
else
    test1   
fi

function GetTime()
{
   echo "Get Time function"
   echo "$# $@"
   if [ "$#" -ne 1 ]; then
       echo "Illegal number of parameters"
   else
       test1
   fi
}

GetTime 
GetTime 2

Giving output as

*** Test ***
1
GetTime
test
Get Time function
0 
Illegal number of parameters
Get Time function
1 2
test

Here for the first call GetTime gives

Get Time function
0 
Illegal number of parameters

Where 0 is the number of parameters passed

and Second call as GetTime 2

produced output

Get Time function
1 2
test

Where 1 is the number of parameters passed and 2 is the argument itself

edited Nov 17, 2014 at 15:11

answered Nov 17, 2014 at 15:04

nu11p01n73R

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2 Comments

anubhava Over a year ago

But GetTime() isn't getting called anywhere.

nu11p01n73R Over a year ago

@anubhava Op might have missed it. I dont think the output is obtainable without a call to GetTime()

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