Why pwd command does not create a process?

Answer 1

Some versions of pwd are internal to the shell, and thus do not need to be executed as a separate process. The command executes so fast you are unlikely to see it on a list of processes, anyway.

Here is a very crude test to show that pwd. when a separate binary, does in fact create a new process. It consists of two scripts with an infinite loop, one constantly running pwd, the other running PS -A and grepping for the word pwd. You will need to console displays or two terminals to test this. Slowly but surely, the script checking for pwd will spit out instances of pwd being run or exiting (defunct).

#/bin/sh

#This script constantly runs pwd. Kill with Ctrl - C

COUNTER=1

while [ $COUNTER -lt 2 ]; do

/bin/pwd

done

#/bin/sh

#This script constantly runs PS -A|grep pwd. Kill with Ctrl - C

COUNTER=1

while [ $COUNTER -lt 2 ]; do

PS -A | grep pwd

done