[gentoo-user] Re: [OT] tar exclude syntax tip

[<nunojsilva@ist.utl.pt> (Nuno Silva)]

On 2021-05-05, tastytea wrote:

> On 2021-05-05 09:33-0400 "Walter Dnes" <waltdnes@waltdnes.org> wrote:
>
>>   tar version
>> 
>> ####################################################
>> tar (GNU tar) 1.34
>> Copyright (C) 2021 Free Software Foundation, Inc.
>> License GPLv3+: GNU GPL version 3 or later
>> <https://gnu.org/licenses/gpl.html>. This is free software: you are
>> free to change and redistribute it. There is NO WARRANTY, to the
>> extent permitted by law.
>> 
>> Written by John Gilmore and Jay Fenlason.
>> ####################################################
>> 
>>   I'm passing on this solution to help others avoid my frustration and
>> wasted time.  If you've done "RTFM" on tar, you'll find out that "TFM"
>> is broken or out-of-date or whatever, re: "--exclude=PATTERN".  I'm
>> fighting the urge to turn this into a rant.  Here's my situation...
>> 
>>   I either log in as root or "su -" and then "cd /home".  I want to
>> tar up /home/waltdnes, and transfer it to another machine.  While I'm
>> at it, I want to exlude directory /home/waltdnes/.cache/ and all *.xz
>> files in directory /home/waltdnes/pm/  The "--exclude=" never worked.
>>  After much hair pulling, I was ready to give up on the exclude, and
>> simply transfer all the unnecessary garbage.
>> 
>>   Then "I asked Mr. Google".  It seems that I wasn't the only person
>> running into problems.  After some searching, I finally found a syntax
>> that works...
>> 
>> ####################################################
>> #!/bin/bash
>> export GZIP=-9
>> tar cvzf wd.tgz --exclude ".cache/*" --exclude "pm/*.xz" waltdnes
>> ####################################################
>> 
>> Notes...
>> 
>> 1) This is obviously not in line with the man page.  Specifically,
>> "--exclude" is followed by one space, not an equals sign.
>> 
>> 2) ***THERE MUST BE EXACTLY ONE SPACE BETWEEN EACH WORD***
>> 
>> 3) All directories and/or files to exclude must be listed as relative
>> paths to the directory being tarred, i.e. last parameter on the
>> command line.
>> 
>> 4) I don't know the maximum line-length, which would limit the number
>> of --exclude entries.  In those cases, I wonder if
>> "--exclude-from=FILE" works as "--exclude-from FILE".
>> 
>
> This works fine here with “tar (GNU tar) 1.34”:
>
> $ mkdir -p a/b
> $ touch a/file a/b/file
> $ touch a/file.xz a/b/file.xz
> $ tree a
> a
> ├── b
> │   ├── file
> │   └── file.xz
> ├── file
> └── file.xz
>
> 1 directory, 4 files
> $ tar -cvzf test.tar.gz --exclude="a/file" --exclude="a/b/*.xz" a
> a/
> a/file.xz
> a/b/
> a/b/file
> $ tar -tf test.tar.gz
> a/
> a/file.xz
> a/b/
> a/b/file
>
> You can find out the maximum length of the command-line with 
> `getconf ARG_MAX`.


But does it work with a space instead of = as well? According to the
online manual page, it should work both ways.

-- 
Nuno Silva