perl command prompt with arguments - perl

Is it possible to start a command prompt from perl script using Win32::Process::Create package?
I am trying to start DOORS from perl script. The executable is present in C:\Program Files\DOORS\bin\runDOORS9.rck.
I need to start the runDOORS9.rck with the argument COL9 to change the Database.

Try the good old system() function. On Windows it would use the cmd.exe, the system shell, to execute the command.
Since what you try to launch doesn't seem to be an .exe file, potentially you would have to use the start command of the cmd.exe.
For example:
system(qq{start "" "C:\Program Files\DOORS\bin\runDOORS9.rck" COL9});
(The first "" is required due to quirky argument parsing of the Window's shell commands. See help start for more information.)

Related

Unable to execute Perl script unless Perl is inserted before script name

Running Lubuntu -
Beginner Perl programmer
Script is XXX.pl located at ~/projects/XXX/XXX.pl
First line is the shebang
#!/usr/bin/perl
Permission to run is set to Anyone.
In directory ~/projects/XXX, the command
~/projects/XXX$ perl XXX.pl
works as desired, but the command
~/projects/XXX$ XXX.pl
Fails with XXX.pl: command not found
What am I missing ?
The two usual options to execute your Perl script are:
perl XXX.pl
or
./XXX.pl
Both ways assume that your current working directory contains the script XXX.pl, otherwise it won't work.
As already pointed out by jm666 in the comments, you can usually not execute a program or script from your current working directory without prepending ./, primarily because of security reasons. Now, you may wonder why it's necessary.
Explanation:
Your shell uses the contents of an environment variable called $PATH to find out about where external commands (non-builtin programs) are located in your filesystem. If you want to see what's in $PATH, just type the following in your shell:
echo $PATH
Now you can see that the $PATH variable does NOT contain your current working directory. The consequence is that your shell is not able to find the program XXX.pl. By prepending ./ you instruct the shell to execute the program which comes after.
But there are two requirements if you want to execute your Perl script with ./script.pl:
The script has to be executable (check with ls -l)
The first line (shebang line) has to be #!/path/to/your/perl because your shell needs that information to find the perl interpreter in order to run your script
However, #1 and #2 are NOT required when you execute your script with
perl XXX.pl
because it invokes the perl interpreter directly with your script.
See how to make Perl scripts executable on Linux and make the script itself directly executable with chmod for some more details.
Can the script be found?
Is . in your path? If it's not, add it to your path, or use ./XXX.pl instead of XXX.pl.
Can the script be executed?
Do you have execute permission to the file? Fix using chmod u+x XXX.pl.
Is the interpreter correct?
which perl will tell you which interpreter is used when you use perl XXX.pl. That's the path that should be on your shebang (#!) line.

#!/bin/bash equivalent in windows / specify interpreter for executable script IN the script

I don't really know which part of the described technology stack the behaviour i'm describing is actually a property of - linux, or bash/sh? but it does not really matter i guess.
Anyway, on linux, in a bash or sh shell, i can run a script marked as executable in the file system without specifying the interpreter on the shell or somewhere global, but right in first line of the file,
e.g.
#!/bin/bash
#!/usr/bin/python
or even
#!/usr/bin/gcl -f
for a common lisp implementation.
Is there a general windows, powershell or cmd.exe equivalent to this?Specifically, specifying the interpreter/command line to run the script with in the script itself, rather than on the command line or in the windows registry.
If not, what are similar options? The most similar thing I know about are shortcuts. Is there something more similar?
In Windows the file extension specifies, which programs is used to Interpret a script.
You can also specify the Interpreter like "cmd": CMD /c "c:\temp\script.cmd" or with Powershell: powershell.exe script.ps1
What you can do (in Powershell) is, to specify the Version, which is used to run the script. Use #Requires -version 3.0 in first line and it will throw error on v4 cmdlets etc.

Perl backtick ignores everything past the first space

I have a command
my $output = `somecommand parm1 parm2`;
When I try to run this Perl script I get the message
Can't exec "somecommand" at .....
It seems it is not seeing anything past the first space in between the backticks. I have a friend who runs this in a different environment and it runs fine.
What could I have in my environment that would cause this? I am running Perl v5.20 but so is my friend.
Perl's not ignoring the command parameters, it's just mentioning only the part of the command that it has a problem with -- it can't find somecommand
Whatever your somecommand is, it's not a shell command and it's not in a directory listed in your PATH variable
Change PATH to add its location to the end and it will work for you. You can do that system-wide or you dan modify it temporarily in your Perl code by manipulating $ENV{PATH} before you run the command

Perl running a batch file #echo command not found

I am using mr on Windows and it allows running arbitrary commands before/after any repository action. As far as I can see this is done simply by invoking perl's system function. However something seems very wrong with my setup: when making mr run the following batch file, located in d:
#echo off
copy /Y foo.bat bar.bat
I get errors on the most basic windows commands:
d:/foo.bat: line 1: #echo: command not found
d:/foo.bat: line 2: copy: command not found
To make sure mr isn't the problem, I ran perl -e 'system( "d:/foo.bat" )' but the output is the same.
Using xcopy instead of copy, it seems the xcopy command is found since the output is now
d:/foo.bat: line 1: #echo: command not found
Invalid number of parameters
However I have no idea what could be wrong with the parameters. I figured maybe the problem is the batch file hasn't full access to the standard command environment so I tried running it explicitly via perl -e 'system( "cmd /c d:\foo.bat" )' but that just starts cmd and does not run the command (I have to exit the command line to get back to the one where I was).
What is wrong here? A detailed explanation would be great. Also, how do I solve this? I prefer a solution that leaves the batch file as is.
The echo directive is executed directly by the running command-prompt instance.
But perl is launching a new process with your command. You need to run your script within a cmd instance, for those commands to work.
Your cmd /c must work. Check if you have spaces in the path you are supplying to it.
You can use a parametrized way of passing arguments,
#array = qw("/c", "path/to/xyz.bat");
system("cmd.exe", #array);
The echo directive is not an executable and hence, it errors out.
The same is true of the copy command also. It is not an executable, while xcopy.exe is.

Disable powershell expansion of command's extension?

We have a lot of existing batch files that help with the running of different perl and ruby scripts.
A batch file (e.g. test.bat) would normally be invoked like:
$ test
and within the batch file, it will set some settings and finally try to run the corresponding script file (e.g. test.pl) like this:
perl -S "%0.pl" %*
All works with cmd.exe, but today, I decided to switch to PowerShell and found out that it expands the commands. So trying to run "test" will actually run "Full\path\test.bat" and my script would complain that there is no file test.bat.pl.
Is there a way to prevent this command expansion? Rewriting all batch files is not an option.
One way is to call cmd explicitly:
cmd /c test