Cshell

A shell implemented in C. Written as a part of Operating Systems (CS39002) coursework.

Functionalities

The following functions have been written explicitly in C.

• cd - Change directory

• pwd - Present Working directory

• mkdir - Make a directory (Alerts if already exists)

• rmdir - Remove the directory (Alerts if no such file or directory)

• ls - List contents of pwd

• ls -l - List the contents in long listing format

• cp - Copy contents of file1 to file2; only if file1 was more recently modified. Create file2 if not present already.

• exit - Exit the shell ; also works for z

• Supports running the execuables (predominanatly, ./a.out and scripting commands, like touch, cat, python notif.py )

• Any path added to your $PATH folder will work. [Refer to function runprocess in shell.c]

• Support background execution such as python notif.py & - returns its PID.

• Input from and output to files, such as ./d < in.txt and ./inc > in.txt supported. (Both can work simultaneously.)

• Support piping upto 2 levels - such as ./inc | ./d and ./inc | ./d | ./t

Execution

Output :

The test cases are present in tests folder.

run.c creates a child process to execute shell.c in a gnome-terminal, suited for debuggging. In case the terminal session is to be viewed in the continuing session, execution is as :

Known issues

• gcc and grep don't work for some freaking reason. Most of the other commands like cat, touc, gedit, atom work but these 2 seem to hold a grudge against me.

• support piping with system calls.