Initial commit
Update head.c to version2
Update head.c to version3.
[Fix] Apply initial value to nlines.
Add grep.c
Add mkdir.c
Add rmdir.c
Add ln.c
Add ls.c
Add symlink.c
Add rm.c
Add mv.c
Add stat.c
Add chmod.c
Add spawn.c
Add env.c
Add daytime.c
Add httpd.c
Add httpd2.c
Add README