I have build a set of libraries and many of my Fortran programs will use them. This creates a problem in that if I ever need to change the location of the libraries then I will need to individually update the path directories in each make file.
How is this usually overcome? I have planned instead to have each make file read a path from a single master path file in the home or root directory (this files location will never change). Within this file is the path for each Library and if any path changes only this file needs to updated.
So I wrote a bash script file, called Master_Library_Paths:
export Library1_Name = {Library1_Name_Path}
echo $Library1_Name
export Library2_Name = {Library2_Name_Path}
echo $Library2_Name
export Library3_Name = {Library3_Name_Path}
echo $Library3_Name
And placed it in my home directory. Then in the make files, I have a line:
$(shell . {Path for Master_Library_Paths} ) \
And load the libraries:
-I$(Library1_Name)
-I$(Library2_Name)
-I$(Library3_Name)
This works great if I run ./Master_Library_Paths in the terminal session first and then go to the directory to compile the program, however that is quite time consuming, How can I fix it so that these arguments Library1_Name, Library2_Name ect are known throughout the system?
New system wide LD_LIBRARY_PATH´s can be added in /etc/ld.so.conf , /etc/ld.so.conf.d/
Or may be in /etc/profile.d/
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Related
I have a Tcl script that works on Windows. When I run it and pass in file names when prompted, usually with a relative directory path. On Windows the script will take absolute OR relative directory paths ... it works, no problems at all.
On Linux it will NOT work in the same way. It will only work if I spell out the full file path, e.g. /home/gxuser/input/test.txt ... It will NOT take relative directory paths like ./input/test.txt
By "work" I mean it should OPEN the file ... It is there and the permissions are fine.
On Linux the program fails with the following error:
couldn't open "./input/test.txt": no such file or directory
while executing
"open $upload r"
The offending line in the code is:
set infile [open $upload r]
What am I doing wrong? I presume, I have overlooked some nuance of the Tcl language, and assumed it should recognize relative paths.
Relevant information:
% puts $tcl_version
8.4
% info patchlevel
8.4.19
% uname -a
Linux gxengine 2.6.32-60-generic #122-Ubuntu SMP
It is possible that a function you call is changing the current working directory. There is no way to tell which one that could be without inspecting the code, but you can check if this is the case by displaying [pwd] before calling open.
Another way things could go wrong is by the script being started in different ways from Unix and Windows - e.g. by shortcut on Windows and from the command line off the PATH on Unix.
Where you have filenames passed in by the user and you can't be sure that code you call won't cd under your feet, you're advised to process the filenames into absolute filenames as soon as possible in your script, possibly even before any package require or source calls.
This is actually easy to do.
set absoluteFilename [file normalize $userProvidedFilename]
As long as this is done before the first cd (or chdir()/SetCurrentDirectory() at the C/C++ level) future changes of directory will not break the path. The script must be prepared to work with absolute filenames, but that's easily done.
You can turn a relative path into an absolute path with respect to any arbitrary directory with file join:
set filename [file join [file normalize $arbitraryLocation] $relativeFilename]
(The file join is smarter than just inserting a directory separator.)
I want to add a small script to the linux PATH so I don't have to actually run it where it's physically placed on disk.
The script is quite simple is about giving apt-get access through a proxy I made it like this:
#!/bin/bash
array=( $# )
len=${#array[#]}
_args=${array[#]:1:$len}
sudo http_proxy="http://user:password#server:port" apt-get $_args
Then I saved this as apt-proxy.sh, set it to +x (chmod) and everything is working fine when I am in the directory where this file is placed.
My question is : how to add this apt-proxy to PATH so I can actually call it as if it where the real apt-get ? [from anywhere]
Looking for command line only solutions, if you know how to do by GUI its nice, but not what I am looking for.
Try this:
Save the script as apt-proxy (without the .sh extension) in some directory, like ~/bin.
Add ~/bin to your PATH, typing export PATH=$PATH:~/bin
If you need it permanently, add that last line in your ~/.bashrc. If you're using zsh, then add it to ~/.zshrc instead.
Then you can just run apt-proxy with your arguments and it will run anywhere.
Note that if you export the PATH variable in a specific window it won't update in other bash instances.
You want to define that directory to the path variable, not the actual binary e.g.
PATH=$MYDIR:$PATH
where MYDIR is defined as the directory containing your binary e.g.
PATH=/Users/username/bin:$PATH
You should put this in your startup script e.g. .bashrc such that it runs each time a shell process is invoked.
Note that order is important, and the PATH is evaluated such that if a script matching your name is found in an earlier entry in the path variable, then that's the one you'll execute. So you could name your script as apt-get and put it earlier in the path. I wouldn't do that since it's confusing. You may want to investigate shell aliases instead.
I note also that you say it works fine from your current directory. If by that you mean you have the current directory in your path (.) then that's a potential security risk. Someone could put some trojan variant of a common utility (e.g. ls) in a directory, then get you to cd to that directory and run it inadvertently.
As a final step, after following the solution form proposed by #jlhonora (https://stackoverflow.com/a/20054809/6311511), change the permissions of the files in the folder "~/bin". You can use this:
chmod -R 755 ~/bin
make an alias to the executable into the ~/.bash_profile file and then use it from anywhere or you can source the directory containing the executables you need run from anywhere and that will do the trick for you.
adding to #jlhonora
your changes in ~./bashrc or ~./zshrc won't reflect until you do
source ~./zshrc or source ./bashrc , or restart your pc
In my workplace, there's one Perl script that runs on a Unix machine every time someone tries to check-in a file to the SVN repo for any of the 10-20 projects.
The way it works is that each project has its own "Hooks" folder with a file called "pre-commit" which SVN automatically executes when someone check-in something. Except the "pre-commit" file is actually a symbolic link to the one central Perl script common to all projects just so that if a change needs to be made to the Perl script it doesn't need to be done for every project.
So my problem is this: I need to put a text file in each of these projects' "hooks" directory, each one containing some settings specific to that project. So there will be 10-20 settings files (one per project) each in their respective "hooks" directory.
The problem is that I need to open these text files in the Perl script and read from them but I'm having issues letting Perl know where to find it. I tried using the $0 parameter which is supposed to tell me where the script is being executed from but because it's a symbolic link it just says "Not a directory" and the script terminates. I need to get the path of the "hooks" directory so that I can find the text file.
The SVN pre-commit script is supposed to be invoked with the path to the repository as its first argument. Inside a Perl script, that argument should be available as $ARGV[0]. You should be able to build the path to the corresponding hooks directory or to a file inside that directory by simply appending to the repository path, like this:
$repopath = $ARGV[0];
$hookspath = $repopath . "/hooks";
$myfilepath = $hookspath . "/myfile";
although for maximum portability it would be cleaner to use the pathname-manipulation functions in the File::Spec module to do this.
If this approach doesn't work then you'll have to explain more about how your Perl script gets invoked. For instance, if your pre-commit script is really a shell script wrapper that eventually invokes perl then perhaps it's not passing the pre-commit arguments along properly.
Showing us your current code that's failing would be a good thing too.
I have a file called x.sh that I want to execute. If I run:
x.sh
then I get:
x.sh: command not found
If I run:
./x.sh
then it runs correctly. Why do I have to type in ./ first?
Because the current directory is not into the PATH environment variable by default, and executables without a path qualification are searched only inside the directory specified by PATH. You can change this behavior by adding . to the end of PATH, but it's not common practice, you'll just get used to this UNIXism.
The idea behind this is that, if executables were searched first inside the current directory, a malicious user could put inside his home directory an executable named e.g. ls or grep or some other commonly used command, tricking the administrator to use it, maybe with superuser powers. On the other hand, this problem is not much felt if you put . at the end of PATH, since in that case the system directories are searched first.
But: our malicious user could still create his dangerous scripts named as common typos of often used commands, e.g. sl for ls (protip: bind it to Steam Locomotive and you won't be tricked anyway :D).
So you see that it's still better to be safe that, if you type an executable name without a path qualification, you are sure you're running something from system directories (and thus supposedly safe).
Because the current directory is normally not included in the default PATH, for security reasons: by NOT looking in the current directory all kinds of nastiness that could be caused by planting a malicious program with the name of a legitimate utility can be avoided. As an example, imagine someone manages to plant a script called ls in your directory, and that script executes rm *.
If you wish to include the current directory in your path, and you're using bash as your default shell, you can add the path via your ~/.bashrc file.
export PATH=$PATH:.
Based on the explanation above, the risk posed by rogue programs is reduced by looking in . last, so all well known legitimate programs will be found before . is checked.
You could also modify the systemwide settings via /etc/profile but that's probably not a good idea.
Because current directory is not in PATH (unlike cmd in Windows). It is a security feature so that malicious scripts in your current directory are not accidentally run.
Though it is not advisable, to satisfy curiosity, you can add . to the PATH and then you will see that x.sh will work.
If you don't explicitly specify a directory then the shell searches through the directories listed in your $PATH for the named executable. If your $PATH does not include . then the current directory is not searched.
$ echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
This is on purpose. If the current directory were searched then the command you type could potentially change based on what directory you're in. This would allow a malicious user to place a binary named ls or cp into directories you frequent and trick you into running a different program.
$ cat /tmp/ls
rm -rf ~/*
$ cd /tmp
$ ls
*kaboom*
I strongly recommend you not add . to your $PATH. You will quickly get used to typing ./, it's no big deal.
You can't execute your file by typing simply
x.sh
because the present working directory isn't in your $PATH. To see your present working directory, type
$ pwd
To see your $PATH, type
$ echo $PATH
To add the current directory to your $PATH for this session, type
$ PATH=$PATH:.
To add it permanently, edit the file .profile in your home directory.
I have a program written in C, which is named computeWeight.c and to compile it i use the following code
chaitu#ubuntu:~$ gcc -Wall -o computeWeight computeWeight.c
//to execute it:
chaitu#ubuntu:~$ ./computeWeight
Do i have any mechansim where i can directly use as mentioned below,
chaitu#ubuntu:~$ computeWeight
Should i be changing any permissions on the executable to get this?
You need to add "." to your path. Some people regard this as dangerous, though. See for instance http://www.arsc.edu/support/policy/dotinpath.html .
The $PATH variable define the places where linux would look for executables (try typing echo $PATH in a terminal). You need to put that file in one of those places. One way is to add a bin folder in your home directory, put the executable file there, and add this line (which adds the bin directory in your home folder to the search path) to your .cshrc file so that it'd be executed for every shell:
set PATH = ($PATH $HOME/bin)
With that said I don't think typing ./ is that bad.
export PATH=$PATH:.