Shell

This is shell61, a shell I built as part of a class. I wrote everything on sh61.c (i.e., the shell implementation) and sh61.h (i.e., token definitions)

Make targets

make sh61 builds the shell's executable sh61

make check runs tests

Supported Commands

After building the sh61 executable by running make sh61, execute it and play around with some of the commands below.

• echo, sleep, grep, wc, sort, cat, true, false, etc.
• background command &
  • sleep 1 & echo hello immediately prints hello, since sleep 1 runs in the background
• commmand lists ;
  • echo hello ; sleep 1 ; echo world prints hello, waits one second, and prints world
• conditionals && and ||
  • true && echo true prints true
  • false && echo false does not print false
  • true || echo true prints nothing
  • false || echo false prints false
• pipelines |
  • echo Bad | grep -c B prints 1
• redirections >, <, and 2>
  • grep sleep < check.pl outputs all lines containing sleep in the check.pl file

Source Files

File	Description
helpers.c	helper functions (e.g., parser)
sh61.c	shell implementation
sh61.h	token definitions