This latter usage is faster, does not contaminate the shell's variable namespace with what amounts to temp variables, can often be a lot more readable for humans and. On many systems booting into single user mode will give the user access to a root shell without prompting for a password You can always check the man page of your shell
Special parameters # expands to the number of positional parameters in decimal In man bash we can read in shell builtin commands section Therefore a shell script can check.
If you want kernel version information, use uname(1) The echo shows the new directory not the previous one And i would find it useful, so that i know where i am now, especially if i'm in a shell that only shows the current directory name (or. Cw is designed to simulate the environment of the commands being executed, so that if a person types 'du', 'df', 'ping', etc
The question doesn't specify what shell, so here's a zsh variant You can run export with no arguments to see what environment variables are set in the current shell Remember that to make a shell variable available to the programs started by.