Re: [Dar-support] Problem using -E option with paths containing spaces

[Denis C. <dar...@fr...>]

Le 11/04/2022 à 15:43, Per Jensen a écrit :
> All,

Hi Per,

> 
> I have an issue making dar (I think) run a par2 script when the path to
> the par2 script has spaces in directory names.

I tried this simple test:

cd /tmp
mkdir "With Space"
cp /bin/ls With\ Space
dar -c test -s 1M -E '/tmp/With\ Space/ls %p/%b.%N.%e' -N
Warning: using insecure memory!
/tmp/test.1.dar
/tmp/test.2.dar
/tmp/test.3.dar
/tmp/test.4.dar
/tmp/test.5.dar
/tmp/test.6.dar
/tmp/test.7.dar
/tmp/test.8.dar
[...]

so to my point of view, there does not seem to be any problem when the
path given to -E option contains space.

[...]

> This works (using escaped spaces in path to the -E option):
> ==========================================
> ➜ ~/.local/bin/dar_static_2.7.4 -Q -c '/tmp/TEST_FULL_2022-04-11' -N -B
> '/tmp/  abc/   def/dar-backup-test/bin/../backups.d/TEST' -E '/tmp/\ \
> abc/\ \ \ def/dar-backup-test/bin/../conf/dar_par_create.duc "%p" "%b"
> "%N" "%e" "%c" 5'
> PAR2 started: "/tmp/  abc/
> def/dar-backup-test/bin/../conf/dar_par_create.duc"
> creating PAR file for file /tmp/TEST_FULL_2022-04-11.1.dar ...


You have to take into account that the command you type on the shell
prompt is first interpreted before being passed to dar. Then the
argument given to -E option is passed to a second shell for execution:

The shell job is to split the long string you type at the prompt, into
words. Words are separated by spaces unless spaces are escaped or when
spaces are quoted (simple quote (') double quoted (") back quote (`) all
having a different meaning for most shells but still avoid space to be
considered as word separator).

So when you type at the shell prompt the following string
	dar -E "Hello world"
the shell CLI parser will provide three words, which I put between
brackets for clarity:
	[dar] [-E] [Hello world]

Note that the double quotes (") have been removed by the shell.
dar is then executed with two arguments [-E] and [Hello world] given by
the shell.

dar's work is then to pass the word following "-E" to a new shell
process. This second shell will read the string [Hello wolrd] as if you
have typed it at the prompt and will also split it into words, leading
to this list of words:
	[Hello] [world]

If the command you want dar to run is not "Hello" but "Hello world" you
have to quote/escape twice the spaces, once for the shell you use to run
dar from, and a second time for the shell that dar runs to interpret the
argument given to -E option.

in my example I can use the following instead of escaping the space(s):

dar -c test -s 1M -E '"/tmp/With Space/ls" %p/%b.%N.%e' -N

[...]

Cheers,
Denis