320sh: Mini-shell with basic operations (a small subset of Bash's functionality)

Launch shell with following command ./320sh

To disable command key capture and job control on the parent shell, use . ./launcher.sh

• The built-in functionalities include: cd,pwd,echo,set,help
• The shell keeps previously typed commands, and allow a user to easily re-issue them with up or down arrow key.
• Backspace and arrow key is supported.
• Command line argument with quote is supported. (e.g. 320sh> ./a.out "This is one argument" )
• Output redirection is supported. It can be accomplshed by three special characters <,>, and |.

Redirection Example
ls -l | sort -k2n
ls -l | grep 2 | wc -l
./a.out < b.txt > out.txt