Shebang line management

[Steve]

Are there any clever ways of dealing with portability of the "shebang"
line... when moving Perl scripts across machines (and across operating
systems), where the path to Perl may be different?

For instance, I'm stuck doing initial development of some CGI scripts
on a Windows machine, but then deploying them to a *nix Apache server.
For each script, I'm manually cut-n-pasting to replace the:

#!"c:/perl/bin/perl.exe"

... with:

#!/usr/bin/perl

I was about to put together a script that would parse all my files and
change the shebang line programmatically, but before doing so I wanted
to see if anyone else had a more elegant approach in their own environment.

 

[A. Sinan Unur]

Are there any clever ways of dealing with portability of the
"shebang"
line... when moving Perl scripts across machines (and across operating
systems), where the path to Perl may be different?

For instance, I'm stuck doing initial development of some CGI
scripts
on a Windows machine, but then deploying them to a *nix Apache server.
For each script, I'm manually cut-n-pasting to replace the:

#!"c:/perl/bin/perl.exe"

... with:

#!/usr/bin/perl

I was about to put together a script that would parse all my
files and
change the shebang line programmatically, but before doing so I wanted
to see if anyone else had a more elegant approach in their own
environment.

This has been asked and answered on this group many times. The question
is somewhat off-topic.

Anyway, myy recommendation is to always use #!/usr/bin/perl with
whatever options you need on the shebang line and read

http://httpd.apache.org/docs/2.2/mod/core.html#scriptinterpretersource

Sinan

 

[John Bokma]

Are there any clever ways of dealing with portability of the
"shebang"
line... when moving Perl scripts across machines (and across operating
systems), where the path to Perl may be different?

For instance, I'm stuck doing initial development of some CGI
scripts
on a Windows machine, but then deploying them to a *nix Apache server.
For each script, I'm manually cut-n-pasting to replace the:

#!"c:/perl/bin/perl.exe"

... with:

#!/usr/bin/perl

I was about to put together a script that would parse all my
files and
change the shebang line programmatically, but before doing so I wanted
to see if anyone else had a more elegant approach in their own
environment.

I use Apache Ant [1]. It also can do stuff like packing all your files
together in a zip, etc. In my experience, the she-bang line might not
be the only thing you want to replace, nor that replacing is limited to
Perl (related) files

example:

<project name="YourProject" basedir=".">
<target name="dist">

<delete dir="build"/>
<mkdir dir="build"/>

<copy file="cgi-bin/script.cgi" todir="build/cgi-bin"/>
<replace
file="build/cgi-bin/script.cgi"
token="#!perl"
value="#!/usr/bin/perl"
/>

<tstamp>
<format property="time.stamp"
pattern="yyyyMMdd-kkmmss"
locale="en"/>
</tstamp>
<delete dir="dist"/>
<mkdir dir="dist"/>
<zip basedir="build"
destfile="dist/${ant.project.name}-${time.stamp}.zip"/>

<delete dir="build"/>
</target>
</project>


ant dist


[1] http://ant.apache.org/

 

[Ben Morrow]

This has been asked and answered on this group many times. The question
is somewhat off-topic.

Huh? How is it off-topic? Is it less OT if I tell you the correct answer
is 'use MakeMaker', which has a facility to do this for you?

That is, package up your scripts into a proper CPAN-like distribution
(it's not difficult), and tweak the Makefile.PL (or Build.PL, if you
must) to install the scripts where you want them. You need to set the
MakeMaker parameter INSTALLSCRIPT to something sensible, probably by
prompting the user to ask where the CGI directory lives (unless you can
work it out).

Ben

 

[A. Sinan Unur]

Huh? How is it off-topic?

I said "somewhat" because I interpreted this as a web server
configuration issue on Windows. There is no need to rely on the shebang
line for Apache on Windows to correctly run CGI scripts. By using
#!/usr/bin/perl, I have avoided the OP's issue for eons. I know there
might be systems where that line may not work, but it has worked for my
purposes.

I felt this might be crossing into a gray area of off-topicyness as the
answer I thought of would have applied to any CGI script written in any
programming language.

Is it less OT if I tell you the correct
answer is 'use MakeMaker', which has a facility to do this for you?

My CGI scripts are usually very short, only five or six lines. The
scripts instantiate the handler object and call its handle_request
method. I have not felt it necessary to use MakeMaker for the scripts
(although the libraries are indeed packaged properly).

That is, package up your scripts into a proper CPAN-like distribution
(it's not difficult), and tweak the Makefile.PL (or Build.PL, if you
must) to install the scripts where you want them. You need to set the
MakeMaker parameter INSTALLSCRIPT to something sensible, probably by
prompting the user to ask where the CGI directory lives (unless you
can work it out).

Good advice if the OP's needs are more sophisticated than mine.

Sinan

 

[Ben Morrow]

I said "somewhat" because I interpreted this as a web server
configuration issue on Windows. There is no need to rely on the shebang
line for Apache on Windows to correctly run CGI scripts. By using
#!/usr/bin/perl, I have avoided the OP's issue for eons. I know there
might be systems where that line may not work, but it has worked for my
purposes.

Fair enough. The question is more general than just Apache-under-
Windows, though.

My CGI scripts are usually very short, only five or six lines. The
scripts instantiate the handler object and call its handle_request
method. I have not felt it necessary to use MakeMaker for the scripts
(although the libraries are indeed packaged properly).

You can include a script (or scripts) in the module distribution, and it
will be installed at the same time. If you can work out where to install
them to in your Makefile.PL, you get 'one-click' CGI installation .

Ben

 

[Jürgen Exner]

Are there any clever ways of dealing with portability of the "shebang"
line... when moving Perl scripts across machines (and across operating
systems), where the path to Perl may be different?

For instance, I'm stuck doing initial development of some CGI scripts
on a Windows machine, but then deploying them to a *nix Apache server.
For each script, I'm manually cut-n-pasting to replace the:

#!"c:/perl/bin/perl.exe"

... with:

#!/usr/bin/perl

Windows doesn't care about the shebang line, therefore you can use the Unix
version even on Windows.

jue

 

[A. Sinan Unur]

Quoth "A. Sinan Unur" <[email protected]>:

Fair enough. The question is more general than just Apache-under-
Windows, though.

I agree

You can include a script (or scripts) in the module distribution, and
it will be installed at the same time. If you can work out where to
install them to in your Makefile.PL, you get 'one-click' CGI
installation .

That makes it easier obviously. I'll follow your advice.

Sinan

 

[A. Sinan Unur]

Windows doesn't care about the shebang line, therefore you can use the
Unix version even on Windows.

Windows shell does not but Apache under Windows does unless the
ScriptInterpreterSource directive is specified in httpd.conf.

Sinan