Simple Shell

List of used functions and system calls

• access (man 2 access)
• chdir (man 2 chdir)
• close (man 2 close)
• closedir (man 3 closedir)
• execve (man 2 execve)
• exit (man 3 exit)
• fork (man 2 fork)
• free (man 3 free)
• getcwd (man 3 getcwd)
• getline (man 3 getline)
• getpid (man 2 getpid)
• kill (man 2 kill)
• malloc (man 3 malloc)
• open (man 2 open)
• opendir (man 3 opendir)
• perror (man 3 perror)
• read (man 2 read)
• signal (man 2 signal)
• strtok (man 3 strtok)
• wait (man 2 wait)
• waitpid (man 2 waitpid)
• write (man 2 write)

Compilation

The shell program can be compiled this way: gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh

Testing

This shell can work like this in interactive mode:

$ ./hsh

($) /bin/ls

hsh main.c shell.c

($)

($) exit

$

But also in non-interactive mode:

$ echo "/bin/ls" | ./hsh

hsh main.c shell.c test_ls_2

$

$ cat test_ls_2

/bin/ls

/bin/ls

$

$ cat test_ls_2 | ./hsh

hsh main.c shell.c test_ls_2

hsh main.c shell.c test_ls_2

$ Some errors with this program hsh:

$ echo "qwerty" | ./hsh

./hsh: 1: qwerty: not found

$ echo "qwerty" | ./././hsh

./././hsh: 1: qwerty: not found $

I wanted to avoid, special IO for terminals.

Ken Thompson