Another sed question.

[Conor P. Cahill]

In article <37091 at ames.arc.nasa.gov>, gahooten at orion.arc.nasa.gov (Gregory A. Hooten) writes:
> #!/bin/sed d1

> What it did was to delete the line starting with the # sign and display all
> of the text that was in the file.  

> My questions are, why do it this way instead of using echo?

Because the programmer wanted to do it that way.  Lots of echos would have
been ugly, but a cat with here documents would have been just as clear and
probably as efficient.

> Why is the # line considered line 1, when it was used
> to start the command in the first space, it seems to me that the line would 
> have already been sent to the terminal to start the sed, and so would not
> be deleted?

Because nothing in the file is "sent to the terminal".  The kernel passes the
entire file to said program.



-- 
+-----------------------------------------------------------------------+
| Conor P. Cahill     uunet!virtech!cpcahil      	703-430-9247	!
| Virtual Technologies Inc.,    P. O. Box 876,   Sterling, VA 22170     |
+-----------------------------------------------------------------------+