CODEWITHSUNDEEP
shell
oz123
oz123

Reputation: 28858

shell - pass function name as parameter

I created a shell script which needed some interactivity in it, so I made the following function:

function check(){
    echo $1
    read ans
    if [ -z $ans ] || [ $ans = "y" ]; then 
        $2 ${*:3}  
    fi 
}

Now I can use this with:

check "shall I greet?" say_hello oz123 stackoverflow 
check "Do you leave?" say_goodbye

Given the functions: 

function say_hello(){

    echo hello $1
    echo hello $2

}

function say_goodbye(){
    echo "Goodbye..."
}

I came up with check by a simple trial, proofing if I can give a function name as a parameter to function. Apparently this is working, but I don't understand why. Can you explain why?

Upvotes: 0

Views: 1095

Answers (1)

oz123
oz123

Reputation: 28858

To expand Etan's comment, here is what man bash says exactly:

SHELL GRAMMAR 

Simple Commands  
A simple command is a sequence of optional  variable  assignments 
followed by  blank-separated  words and redirections, and terminated by a
control operator. The first word specifies the command to be executed,
and  is  passed  as  argument  zero. The remaining words are passed as
arguments to the invoked command.

I wish I knew this earlier, it can make bash scripts much more constructed and easier to write and read.

Upvotes: 1

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