A question about intrinsic command in shell

[Wang,MinJie]

As we all know,Posix-Shell has its own intrinsics such as ls,cd and so on, while these commands are also available as unix command and exist in the file system(like "ls").So I want to know that when I run "ls" in the shell,which command will it actually run? The shell intrinsics or unix command which locates in the unix file system and prove that?
Thx in advance

[Steven Schweda · Accepted solution]

"ls"?

td176> type ls
ls is a tracked alias for /usr/bin/ls

td176> type cd
cd is a shell builtin.

If you want "/bin/ls", then _say_ "/bin/ls".

man sh

man sh-posix

[Peter Godron]

Hi,
please see:
http://www.robelle.com/library/smugbook/whence.html

For Korn shell,I would use whence, which is going to tell you what you are running.
For your Posix, type.

Earlier thread with a similar theme:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=706680

[Dennis Handly]

Basically cd has to be builtin. While the shell can do "globbing", to expand wildcards, ls(1) is still done by the command.

Besides Pete's mention of whence, you can look at the sh-posix or ksh man pages and look under "Special Commands" for builtins.