sltsh

a toy shell (no programming feature)

Features Supported:

• subshell : ()
• pipeline : |
• background : &
• exec in order : ;
• built-in commands
• redirection
• expansion

Built-in:

• jobs
• fg
• bg
• umask (no arg to see the current value, or 0000~0777 to set)
• cd (no arg to go to home directory)

Redirection:

• >file, >>file, fd>file, fd>>file, fd>&fd, >&file, <file

Expansion:

• command substitution:
  • cd /usr/src/kernels/$(uname -r)
• arithmetic expansion:
  • echo $((3+4*5))
• tilde expansion:
  • cd ~/bin

Grammar:

CmdLine = CmdList ENDOFLINE
CmdList = Pipe
		| Pipe Delim CmdList
		| Pipe Delim
Delim = ; | &
Pipe = Redirected
	 | Redirected '|' Pipe
Redirected = Primary
		   | Primary [redirectflags]
Primary = Exec
		| (CmdList)

Installation

make