Tar did a weird thing today
from tasankovasara@sopuli.xyz to linux@lemmy.ml on 19 Sep 17:17
https://sopuli.xyz/post/33939450

I’m so baffled I had to ask – why this behaviour?

cd /var/www/html
tar czf ~/package.tgz admin/* api/* mobile/*

I do this, and the resulting package doesn’t include a couple of hidden files – api/.htaccess and admin/.htaccess. However…

cd /var/www/html
tar czf ~/package.tgz *

This time the hidden .htaccess files are there.

Does anybody have enlightenment to offer as to why?

#linux

threaded - newest

T4V0@lemmy.pt on 19 Sep 17:41 next collapse

Probably due to wildcard expansion by the shell. Use dot (.) instead of asterisk (*).

nous@programming.dev on 19 Sep 17:45 next collapse

* in your commands is expanded by the shell before tar sees them. It also does not expand hidden files.

So when you do admin/* the shell expands to all non hidden files inside admin. Which does not include admin/.htaccess. So tar is never told to archive this file, only the other non hidden files and folders. It will still archive hidden files and folders nested deeper though.

In the second example * expands to admin and the other does which are not hidden at that level. Then tar can open these dirs and recursivly archive all files and folders including the hidden ones.

You can see what commands actually get executed after any shell expansions if you run set -x first. Then set +x to turn that off again.

Here is an example using ls:

$ set -x; ls -A foo/*; ls -A *; set +x
+ ls --color=tty -A foo/baz
foo/baz
+ ls --color=tty -A foo
.bar  baz
+ set +x
sun_is_ra@sh.itjust.works on 19 Sep 21:09 collapse

A quicker way to test this is by using echo

try echo tar czf ~/package.tgz admin/* api/* mobile/*

RheumatoidArthritis@mander.xyz on 19 Sep 17:46 next collapse

unix.stackexchange.com/…/what-is-the-setting-in-b…

[deleted] on 19 Sep 17:54 next collapse

.

vk6flab@lemmy.radio on 19 Sep 17:58 next collapse

You don’t need the wildcard, and as others have pointed out, it doesn’t include "hidden " dot files by default.

tar -czf ~/package.tgz admin api mobile

balsoft@lemmy.ml on 19 Sep 20:04 next collapse

Ah yes, one of the biggest bugs-later-turned-design-mistakes of UNIX. This is not tar, this is your shell; you always need to use both * and .* for a wildcard to match all files in directory - e.g. tar czf ~/package.tgz admin/* admin/.* api/* api/.* mobile/* mobile/.*

BCsven@lemmy.ca on 20 Sep 01:10 next collapse

Could this be made easier by setting globstar or dotglob options, to include hidden files but not try to grab . and … Directory files

tasankovasara@sopuli.xyz on 20 Sep 12:10 collapse

Thanks - this is what I did with a ‘you had one job’ look beaming at the terminal after realising the hidden files were missed and indeed it did the trick.

tasankovasara@sopuli.xyz on 20 Sep 12:16 next collapse

Thank you all! Over 25 years on Linux and still new learnings to discover…

[deleted] on 21 Sep 15:07 next collapse

.

corsicanguppy@lemmy.ca on 21 Sep 15:47 collapse

This is potentially a great ‘weeder’ question for junior Unix admin interviews, as it requires some knowledge about shell globbing and tar dir traversal.

I admit it took me a sec (and a second read) before I got it, so it was a fun “hey what” exercise.

Excellent question.

neclimdul@lemmy.world on 22 Sep 00:17 collapse

Dang as soon as you said globbing I realized what had happened but didn’t see it right away either