Unix tip of the day

[yesthattom]

For years I've taken advantage of the fact that one can use the "+" option in "vi" to have the editor open up at a particular position:

Example: Open the file file.txt for editing and position cursor at the 5th line:
vi +5 file.txt

Today I saw a shell script that opened to line "$" which positions the cursor at the last line. It's obvious that it would work ("$" means "last line" in the vi command line) but I had never thought of it:
vi +$ file.txt

Comments

[qnetter]

Then I guess you're even less likely to be aware of:

   vi +/foo/ file.txt

[yesthattom.livejournal.com]

Oddly enough, I've known and used that idiom for a while.

[dossy.livejournal.com]

The humor here is that "$" means "end of line" not end of buffer, and that what you discovered is that "vi +" positions you at the end of the edit buffer, and that your shell is eating "$" silently as a shell metachar.

LOL. :-)

[yesthattom.livejournal.com]

My shell doesn't eat the "$" since it is followed by a space.

However, if you do "vi +\$ file.txt" vi takes me to the end of the buffer, not end of the line.

In vi "$" means "last line" when in a line-number context. For example:

%s/search/replace/g
is the same as
1,$s/search/replace/g

% (all lines) is just an alias for "1,$" (from the first to the last).

This behavior was copied by awk.

[dossy.livejournal.com]

Ah, yes, you're right, in a line context, "$" does mean "end of buffer" ... but in this case, vim at least treats "vi +" and "vi +$" both as "end of buffer."

[geekosaur]

Yep, vi + file has meant "open at end" ever since the original vi. And you can use any ex-level command after the +... which is why POSIX renamed it -c (since options not starting with - are verboten...).