I have just added this script to PATH variable, but it does not work.
I need to use it in any directory as:
perl script.pl SOME ARGUMENTS
I have windows 7 Ultimate.
Thank you for advices!
While the system is using PATH to find the program to run, the system is executing perl, not script.pl.
Either tell perl to search PATH for the script,
perl -S script.pl SOME ARGUMENTS
Or launch the script directly.
script.pl SOME ARGUMENTS
Windows will use file associations to determine how to launch the file in the latter case.
Related
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.
I am trying to run a perl script from within a *.csh script, but I get the following error:
Can't open perl script "checkLength.perl": No such file or directory
I think it has something to do with the path of the perl script. I can run a perl script fine when it's not being called within the shell script, but a perl script won't run when I have it being called in the cshell script.
The shebang I use for the perl script is : #!/usr/bin/perl. I checked, and perl is located there (not in /usr/bin/env perl). I made sure it's executable.
Do I need to edit the $PATH to get this to work? I'm confused because if I run a perl script without calling it within another csh script, it runs just fine.
Of course one obvious solution to your problem would be to simply use the full path to the script. But this is often not preferable, as the script would brake on installations that do not mirror exactly the original structure.
So there are two possibilities:
Either you put your perl script into a well defined location that is contained in your PATH variable so any program that runs under the respective users environment finds it.
Or you have some well defined location relative to the location of your calling script. Say your bash script is located in somedir and you perl script is in somedir/subdir, then your call would be subdir/perlscript.pl. Then, to become independent of possible changes in the working directory of the caller, you could determine the current full path of the perl script to be called on start of the bash script.
A template for this would be:
#!/bin/bash
FULLPATH=$(pwd)/subdir/somescript.pl
# do something else, cd ...
$FULLPATH
I am assuming your Perl script is kept in a fixed path relative to your bash script. Assuming your directory structure to be like so:
(BASEDIR)/bin/example.sh
(BASEDIR)/perl/example.pl
To allow you to run your bash script from anywhere in your system you must specify the relative path to your Perl script by getting the BASEDIR.
#!/bin/bash
BASEDIR=$(dirname $0)
perl $BASEDIR/../perl/example.pl
What we are doing above is finding the location of your bash script(BASEDIR/bin) that you call and then finding the relative location of the Perl script using the location of the bash script as reference. Now you will be able to call the bash script from anywhere and run your Perl script normally.
I have a series of perl scripts that I want to run one after another on a unix system. What type of file would this be / could I reference it as in documentation? BASH, BATCH, Shell Script File?
Any help would be appreciated.
Simply put the commands you would use to run them manually in a file (say, perlScripts.sh):
#!/bin/sh
perl script1.pl
perl script2.pl
perl script3.pl
Then from the command line:
$ sh perlScripts.sh
Consider using Perl itself to run all of the scripts. If the scripts don't take command line arguments, you can simply use:
do 'script1.pl';
do 'script2.pl';
etc.
do 'file_name' basically copies the file's code into the current script and executes it. It gives each file its own scope, however, so variables won't clash.
This approach is more efficient, because it starts only one instance of the Perl interpreter. It will also avoid repeated loading of modules.
If you do need to pass arguments or capture the output, you can still do it in a Perl file with backquotes or system:
my $output = `script3.pl file1.txt`; #If the output is needed.
system("script3.pl","file1.txt"); #If the output is not needed.
This is similar to using a shell script. However, it is cross-platform compatible. It means your scripts only rely on Perl being present, and no other external programs. And it allows you to easily add functionality to the calling script.
Problem: Windows XP is not passing command line arguments to perl scripts.
Symptom: a simple command like:
say "Argument 1 (\$ARGV[0]) is: $ARGV[0], argument 2 (\$ARGV[1]) is: $ARGV[1].";
Resulted in:
Use of uninitialized value $ARGV[0] in concatenation (.) or string at...
Solution:
The root problem is in Windows XP. The default method for starting perl passes only the first variable, which is the script name. Result is that $ARGV[0] is uninitialized.
The fix is to edit the Windows registry at:
\HKEY_CLASSES_ROOT\Perl\shell\Open\command
And make the entry:
"C:\Perl\bin\perl.exe" %*
Result is:
C:\whatever>perl argtest.pl 1 2
Argument 1 ($ARGV[0]) is: 1, argument 2 ($ARGV[1]) is: 2.
Thanks especially to David W who pointed me in the right direction.
Note that #ARGV in Perl is not quite like argv in C.
C Perl
Name of the program argv[0] $0
1st argument argv[1] $ARGV[0]
2nd argument argv[2] $ARGV[1]
n-th argument argv[n] $ARGV[n-1]
So if you provide one command line arguments to a Perl script, it will be found in $ARGV[0]. $ARGV[1] will be uninitialized.
Download Cygwin and test your code in the Cygwin environment. I bet this is a Windows issue. (If you're a Unix head, you'll like Cygwin because it gives you the Unix/Linux like environment on your Windows machine. I don't use Windows without it.)
Windows uses suffixes to determine what program opens what files. Is your Perl script called argtest, argtest.bat or argtest.pl?
On Windows, make sure all of your Perl scripts use the *.pl suffix, so Windows will use whatever Perl parameter to execute them. Windows doesn't use the shebang.
Another possible issue: On Windows XP, I had a problem with Perl scripts with parameters because Windows had this as an execution string:
perl %1
which would execute the Perl program with my script, but ignore the parameters. I had to change this to:
perl %*
Unfortunately, Windows Vista through Windows 8 changed the way this is set. However, I have Windows 7 and don't have this issue. I did make sure to install Perl under C:\Perl and not C:\Program Files\Perl because of the space in the directory name. I also have Strawberry Perl installed.
There is a special Windows environment variable called PATHEXT. This allows you to type in foo instead of foo.pl. If Windows can't see how to execute your file, Windows goes through %PATHEXT and tries appending various suffixes until it finds one that works. You might want to append .PL to that environment variable, so you can type in foo instead of foo.pl all the time.
There are two ways that Windows knows it is supposed to use Perl to execute a program.
The command line begins with the perl executable and the name of the script to be run is provided as a command line argument. This is how it works on Unix and other environments, too.
Your system associates one or more extensions, such as .pl, .pm, and/or .cgi with the Perl application, and Windows will launch Perl when you type a filename with one of those extensions or click on a file with one of those extensions in the Windows explorer.
You have invoked your script simply as
argtest 1 2
and not one of
perl argtest 1 2
argtest.pl 1 2
That makes me think that Perl is not the first application that gets to look at the file referred to by argtest. Perhaps there is a file called argtest.bat or argtest.exe which has the task of getting Perl to run your Perl code. For some reason this intermediate program is not passing the command line arguments that you provide on to the Perl application.
Provide the code for this intermediate file and we can help some more.
UPDATE: David W proposes a 3rd way -- setting the PATHEXT environment variable to inclue .pl files and invoking argtest from the command-line -- see his answer.
Then if Window's file association with the .pl extension was messed up, say, set as just C:\Dwimperl\perl\bin\perl" and not "C:\Dwimperl\perl\binperl %*" then the OP would get the behavior that he describes.
In perl file name is not part of the array of arguments. At least in the test I did you must remove ARGV[2] or pass three arguments, like argtest 1 2 3
Maybe it's dumbest question in the world, but I seriously have problems with it and could use help. I am trying to run perl script on linux. It's a simple text editing script, nothing fancy. I googled for it and I found that I had to chmod +x it and then just run myscript.pl in the console. Since it's supposed to modify a text file I did myscript.pl > myfile.txt after chmoding it
But it doesn't work. I get: bash: perl myscript.pl: command not found
Unless myscript.pl is in your path you will need to specify the current directory.
$ ./myscript.pl
You can check if the current directory is in your path with $ echo $PATH. If you're frequently using this script you can put it in the path by moving it to a directory that's part of your path, usually ~/bin.
Or by adding the current directory to the $PATH environment variable. Check the documentation for your shell for instructions.
Can you post the first few lines of your script?
Specifically, if you have #!/usr/bin/perl are there any typos on that line, extra spaces, etc.?
Also do a ls /usr/bin/perl (or whatever is on that line) to make sure it's actually there.
It doesn't look like perl is installed on your Linux machine. Do you get the same thing when you try this: # perl -e 'print "hi";' ?
As Chirael said, it sounds like your shebang line (the directive at the top of the file, that tells the shell how to run the script) is invalid somehow. You can bypass the shebang line entirely by invoking your script as:
perl myscript.pl > myfile.txt
You also don't need to set the script's executable bit, as with this method of invocation, you are only reading the script, not executing it (from the shell's perspective).
According to this thread, it could be from different representation of the new line.
Have you written the script on a windows box and copied over to your linux box?
What is your text editor?
I had the same issue, and traced it to DOS line endings (^M). Running dos2unix on the .pl file fixed the issue.
Please use,
./myperl.pl > outfile.txt
to give the current directory path
thanks