Unix, find command, and false negative

Question

Performing a search from the current directory where this file resides, this find command finds the file.

# find . page.tpl.php

However, when I search from a child directory, this command,

# find ../. page.tpl.php

prints out the list of files, WITH the requested file listed in the output,

.././parent_dir/page.tpl.php

However, the results are,

find: `page.tpl.php': No such file or directory

Then when I add the -name argument it works,

# find ../. -name page.tpl.php

I simply forget to use arguments sometimes and the false negative is really aggravating. What's going on?

• dmckee --- ex-moderator kitten: There is no false negative here. The program has done exactly what you asked and returned the correct results. A better question would be "Why does find have such funny commandline syntax?" or "What exactly is find doing here?"
• xtian: I believe my question to be appropriate. If you want to ask a "better question" you are, of course, free to do so.
• xtian: Follow-UP Trying RedGrittyBrick's advise, I used the relative path .. instead of ../. on another file "ts-unix-find" and this time it worked. I thought I made a mistake in my post. Then I noticed the dot syntax. Sure enough, when I renamed the file "ts-unix-find.save" and performed the first two find commands above, I repeated the behavior. Evidently a find command with a relative path .. and an "expression" containing a dot doesn't work. Now I want to understand this "expression" distinction... (^_^)

Answer 1

find [path] [expressions]

A filename isn't an expression.

The default action is to print.

For path, ".." is better than "../." you almost never need to include "." unless it's at the start of a relative path.

• xtian: Ok. I appreciate the methodical way you answered my post. That a file name isn't an expression is a lost distinction, which is to say I know you are making a distinction, but I don't understand what it means. And the default print action is perfectly fine. Actually I would want to force the print action when using -name, but it remains silent. I tried .. and learned something which is in a comment follow-up...

Answer 2

The command find uses:
find [-H] [-L] [-P] [path...] [expression]

Your first example was:
find ../. page.tpl.php

What you did was give find two search paths. As the default expression is print, the contents of the two paths were printed to stdout.

Consider this:

mkdir a b c 
touch a/file1 a/file2 b/SANTACLAUS c/MONKEYS
find a b
$ find a b
a
a/file2
a/file1
b
b/SANTACLAUS

Your second example was:
.././parent_dir/page.tpl.php

Here you provided one search path. The error tells you that page.tpl.php wasn't found in CWD. I assume this was due to your not having the file 'page.tpl.php' under the directory 'parent_dir'.

• xtian: No. The file was there. I first performed the find in the same directory. Then descended into a child directory and performed the same find with the relative path ../. I never moved the file, it was still there.