I need to call the function called foo() using echo command in the same statement. How do I all or invoke the function using the echo statement?

You can define a function using the following syntax:

foo(){
    date
}

Now you can call the function foo() using the echo statement as follows:

echo "Today is $(foo)"

Sample outputs:

Today is Sat Jan 22 00:27:26 IST 2011

A sample shell script to display system info:

#!/bin/bash
findcpu(){
	grep 'model name' /proc/cpuinfo  | uniq | awk -F':' '{ print $2}'
}
 
findkernelversion(){
	uname -mrs
}
 
totalmem(){
	grep -i 'memtotal' /proc/meminfo | awk -F':' '{ print $2}'
}
 
echo "CPU Type : $(findcpu)"
echo "Kernel version : $(findkernelversion)"
echo "Total memory : $(totalmem)"

See also:

• Chapter 9: Functions from the Linux shell scripting wiki.