[Discuss] php question. change directory to executing script.

[Eric Chadbourne]

Excellent points Mike, particularly on symlinks.  I'll make it a variable as suggested.

Thanks,
Eric Chadbourne

> -------- Original Message --------
> Subject: Re: [Discuss] php question. change directory to executing script.
> Local Time: December 19, 2017 10:52 AM
> UTC Time: December 19, 2017 3:52 PM
> From: smallm at sdf.org
> To: Eric Chadbourne <sillystring at protonmail.com>
> BLU <discuss at blu.org>
>
> Eric Chadbourne sillystring at protonmail.com writes:
>
>> Hi All,
>> I have a little function that needs to delete some files. I don't
>> want it to delete them from the directory of my user, but in the
>> directory of the script.
>> For example from terminal:
>> cd $HOME
>> php /path/to/script/foo.php // will execute foo in home
>> But I want it to execute foo in /script.
>> So in the function I told it to change working directory to script path.
>> chdir(dirname(FILE));
>> Am I missing something or is this OK? Is it evil to do such a thing?
>>
>> Could your script ever be a symlink? Seems to me I've seen this go wrong
>> or at least get confusing (yes, it seems not uncommon to want to run
>> things in the script's directory - each place I've worked at the last 20
>> years has done it, both under Linux and under Windows) when symlinks are
>> involved.
>>
>> What about passing an argument with the directory to execute in. Then at
>> least you have outside control. It's kind of the moral equivalent of a
>> local (or really a function argument) vs. global variable, in the sense
>> that your script's directory is like a global in that it comes from the
>> surrounding environment and isn't stated explicitly vs. a command
>> argument which would be more like (and end up in) a local variable.
>>
>> It it's clumsy to run that way you can always use an alias.
>>
>> On the other hand if its your own thing make it as simple as works for
>> you. Maybe you don't care about symlinks, and it's small enough that
>> "global variables" are appropriate. I just recall at the Windows job
>> when the program got big new programmers were a bit puzzled about which
>> directory it ran in and where it found its configuration files. It was
>> yet another bit of annoying incidental knowledge to be passed on that
>> the "working directory" wasn't the normal working directory but the
>> program's directory, or subdirectories relative to that.
>>
>> --
>> Mike Small
>> smallm at sdf.org