I wrote a perl script that prints a path to a very specific file. I want to define a personal environment variables (by using setenv in .aliases file) that gives the output of this script.
For example, let's say that the file "myscript.pl" prints the path "/home/files/reports/file". Let's call the variable (that I want to define in .aliases file) 'myoutput'. I want that when I type "most $myoutput" in Unix, this file will be opened by most, and when I type "echo $myoutput", Unix will print the path.
How can I define a personal variable which value is determined by a script?
If you use bash, you can put the following to your .bashrc:
export myoutput=$(perl /path/to/myscript.pl)
For tcsh, use .cshrc instead, and modify the line to
setenv myoutput `perl /path/to/myscript.pl`
You need to start a new session to make the variable exist.
myoutput=$(perl myscript.pl)
When your script prints more, select the correct line:
myoutput=$(perl myscript.pl | grep /home)
Related
I have the following code in a perl module,
package Foo;
our $pathToScript = "/home/Lucas/project841/python_script.py";
It is frequently called by other modules in the same file directory through
$output = `$Foo::pathToScript`;
# etc
I would like to remove the hard coding of the actual path and use relative path, Eg. ./python_script.py to call the script from other modules.
What would be the ideal way?
You said your Perl script is "frequently" called from the same directory where the Python script resides, not "always". If you remove the absolute path, you'll need to change that "frequently" to "always", and just change $pathToScript to the Python script name (no path).
You could also consider setting the environment PATH (in the Perl script) so that the Python script (without the full path in $pathToScript) is always found, regardless of where the user is running from or where the Perl script is located.
I have a script in one of my application folders.Usually I just cd into that locatin in Unix box and run the script e.g.
UNIX> cd My\Folder\
My\Folder> MyScript
This prints the required result.
I am not sure how do I do this in Bash script.I have done the following
#!/bin/bash
mydir=My\Folder\
cd $mydir
echo $(pwd)
This basically puts me in the right folder to run the required script . But I am not sure how to run the script in the code?
If you can call MyScript (as opposed to ./MyScript), obviously the current directory (".") is part of your PATH. (Which, by the way, isn't a good idea.)
That means you can call MyScript in your script just like that:
#!/bin/bash
mydir=My/Folder/
cd $mydir
echo $(pwd)
MyScript
As I said, ./MyScript would be better (not as ambiguous). See Michael Wild's comment about directory separators.
Generally speaking, Bash considers everything that does not resolve to a builtin keyword (like if, while, do etc.) as a call to an executable or script (*) located somewhere in your PATH. It will check each directory in the PATH, in turn, for a so-named executable / script, and execute the first one it finds (which might or might not be the MyScript you are intending to run). That's why specifying that you mean the very MyScript in this directory (./) is the better choice.
(*): Unless, of course, there is a function of that name defined.
#!/bin/bash
mydir=My/Folder/
cd $mydir
echo $(pwd)
MyScript
I would rather put the name in quotes. This makes it easier to read and save against mistakes.
#!/bin/bash
mydir="My Folder"
cd "$mydir"
echo $(pwd)
./MyScript
Your nickname says it all ;-)
When a command is entered at the prompt that doesn't contain a /, Bash first checks whether it is a alias or a function. Then it checks whether it is a built-in command, and only then it starts searching on the PATH. This is a shell variable that contains a list of directories to search for commands. It appears that in your case . (i.e. the current directory) is in the PATH, which is generally considered to be a pretty bad idea.
If the command contains a /, no look-up in the PATH is performed. Instead an exact match is required. If starting with a / it is an absolute path, and the file must exist. Otherwise it is a relative path, and the file must exist relative to the current working directory.
So, you have two acceptable options:
Put your script in some directory that is on your PATH. Alternatively, add the directory containing the script to the PATH variable.
Use an absolute or relative path to invoke your script.
I have around 230 files which are *.pl , *.txt and some are *.conf files which has a default path set to the current environment say /home/AD/USR/perl/5.8.0/bin/perl. I need to replace "/home/AD/USR" with an environment variable ${USR_PATH}. The files I want to modify are in subdirectories. Which means my script should find e.g find .|xargs grep -l "/home/AD/USR" all the files and then replace the string.
OLD: /home/AD/USR/perl/5.8.0/bin/perl
New : ${USR_PATH}/perl/5.8.0/bin/perl
Can some one give me a clue how do I do that?
Shell : /bin/bash
Env : Linux x86_64
If you replace part of a string with ${USR_PATH} you will refer to the perl variable $USR_PATH, not the environment variable, which is in perl referred to as $ENV{USR_PATH}.
perl -pi.bak -we 's#/home/AD/USR(?=/perl/5.8.0/bin/perl)#\$ENV{USR_PATH}#g'
*.pl *.txt *.conf
Using the lookahead will save you the trouble of replacing the rest of the path afterwards.
I assume you want to replace it with the literal value. If you want to replace it with the actual value in the environment variable, just remove the backslash in front of $ENV.
While using an environment variable seems handy and all, it will reduce your scripts portability. Why not use a configuration file? If you had done that from the start, you wouldn't be having this trouble. Search CPAN for a nice module.
perl -i -pe 's|/home/AD/USR/perl/5.8.0/bin/perl|\${USR_PATH}/perl/5.8.0/bin/perl|' <your files>
I am trying to find a way to register the files with extension .pl as executables.
I spent some time on the web looking for a solution, but I couldn't find anything.
What I can do:
I made a script, let's call it myscript.pl
I can run it like this :
perl myscript.pl [my_script_parameters]
Now since the file is associated with perl, I can also run it as:
myscript.pl [my_script_parameters]
Now, I know that there is somewhere a list of extensions that are considered as executables (.exe, .bat, etc…). I would like to add .pl to this list so that I can run my script like this:
myscript [my_script_parameters]
Does anyone know how to do this?
Yes, there is built-in support for this. If you check the help for command FTYPE you will see a perl example.
C:>help ftype
Displays or modifies file types used
in file extension associations
FTYPE [fileType[=[openCommandString]]]
fileType Specifies the file type to
examine or change openCommandString
Specifies the open command to use when
launching files
of this type.
Type FTYPE without parameters to
display the current file types that
have open command strings defined.
FTYPE is invoked with just a file
type, it displays the current open
command string for that file type.
Specify nothing for the open command
string and the FTYPE command will
delete the open command string for the
file type. Within an open command
string %0 or %1 are substituted with
the file name being launched through
the assocation. %* gets all the
parameters and %2 gets the 1st
parameter, %3 the second, etc. %~n
gets all the remaining parameters
starting with the nth parameter, where
n may be between 2 and 9, inclusive.
For example:
ASSOC .pl=PerlScript
FTYPE PerlScript=perl.exe %1 %*
would allow you to invoke a Perl
script as follows:
script.pl 1 2 3
If you want to eliminate the need to
type the extensions, then do the
following:
set PATHEXT=.pl;%PATHEXT%
and the script could be invoked as
follows:
script 1 2 3
You can simply add ";.PL" to the PATHEXT environment variable. Right-click "My computer" > Properties > Advanced > Environment variables > System variables.
Your best approach would be to write a batch file called myscript.bat, place it in your path, and have it run your script.. e.g.
#echo off
c:\perl\bin\perl.exe c:\scripts\myscript.pl %*
I am trying to use diffstrings.py from Three20 on my iPhone project, and I can't find the proper format for the path arguments (as in "Usage: diffstrings.py [options] path1 path2 ...").
For example, when I run the script in my Xcode project directory like this
~/py/diffstrings.py -b
it analyzes just the main.m and finds 0 strings to localize,
then it diffs against existing fr.lproj and others, and finds that thes contain "obsolete strings".
Can anyone post examples of successful comand line invocations of diffstrings.py, for options -b, -d and -m?
Taking a quick look at the code here http://github.com/facebook/three20/blob/master/diffstrings.py I see that if you don't specify any command line options, it assumes you mean the directory wherever the script lives in. So the option is to either copy .py file to where your .m files are, or simple use the command
~py/diffstrings.py -b .
That is, give the current directory (.) as the path argument.