I am currently learning LINUX commands and I am wondering how to run commands within the .plan file.
For example i want to a message as would be output from the ~stepp/cosway programs.
I typed ~stepp/cosway "HELLO" but it didn't work. What is the command for that?
Also how do I set all files in the current directory and all its subdirectories recursively to have a group of admin?
The .plan file is a plain text file that is served by the fingerd daemon. For security reasons, it's not possible to execute commands from that file, unless you modify and recompile fingerd on your machine to do so.
Concerning the second part of your question, use chgrp:
$ chgrp -R admin *
Related
I feel like I'm missing something very basic so apologies if this question is obtuse. I've been struggling with this problem for as long as I've been using the bash shell.
Say I have a structure like this:
├──bin
├──command (executable)
This will execute:
$ bin/command
then I symlink bin/command to the project root
$ ln -s bin/command c
like so
├──c (symlink to bin/command)
├──bin
├──command (executable)
I can't do the following (errors with -bash: c: command not found)
$ c
I must do?
$ ./c
What's going on here? — is it possible to execute a command from the current directory without preceding it with ./ and also without using a system wide alias? It would be very convenient for distributed executables and utility scripts to give them one letter folder specific shortcuts on a per project basis.
It's not a matter of bash not allowing execution from the current directory, but rather, you haven't added the current directory to your list of directories to execute from.
export PATH=".:$PATH"
$ c
$
This can be a security risk, however, because if the directory contains files which you don't trust or know where they came from, a file existing in the currently directory could be confused with a system command.
For example, say the current directory is called "foo" and your colleague asks you to go into "foo" and set the permissions of "bar" to 755. As root, you run "chmod foo 755"
You assume chmod really is chmod, but if there is a file named chmod in the current directory and your colleague put it there, chmod is really a program he wrote and you are running it as root. Perhaps "chmod" resets the root password on the box or something else dangerous.
Therefore, the standard is to limit command executions which don't specify a directory to a set of explicitly trusted directories.
Beware that the accepted answer introduces a serious vulnerability!
You might add the current directory to your PATH but not at the beginning of it. That would be a very risky setting.
There are still possible vulnerabilities when the current directory is at the end but far less so this is what I would suggest:
PATH="$PATH":.
Here, the current directory is only searched after every directory already present in the PATH is explored so the risk to have an existing command overloaded by an hostile one is no more present. There is still a risk for an uninstalled command or a typo to be exploited, but it is much lower. Just make sure the dot is always at the end of the PATH when you add new directories in it.
You could add . to your PATH. (See kamituel's answer for details)
Also there is ~/.local/bin for user specific binaries on many distros.
What you can do is add the current dir (.) to the $PATH:
export PATH=.:$PATH
But this can pose a security issue, so be aware of that. See this ServerFault answer on why it's not so good idea, especially for the root account.
About a year ago, I created a couple text files called "compile" and "pull." When I go into a cygwin prompt and type those names and hit enter (basically use them as a command), the cygwin terminal runs what is in those text files. For instance here is the contents of one:
git checkout master
git checkout -- .
I don't even remember how I did this. I'm pretty sure this is not a bash script.
I do remember that I had to not just create the file in notepad but also perform some linux command line operation on it, in order to use it. Once I did that I could basically use the file as a command.
In *nix, you have to make a file executable in order to be able to run it:
chmod u+x file
You also need to add the path to the file to the PATH variable
PATH=$PATH:/path/to/the/file
or, add . to always scan the current directory for commands (it's considered unsecure, though):
PATH=$PATH:.
In my work, I use 2 Linux servers.
The first one is used for web-crawling and create it as a text file.
The other one is used for analyzing the text file from the web crawler.
So the issue is that when a text file is created on web-crawling server,
it needs to be transferred automatically on the analysis server.
I've used shell programming guides referring some tips,
and set up the crawling server to be able to execute the scp command without requiring the password (By using ssh-keygen command, Add ssh-key on authorized_keys file located in /root/.ssh directory)
But I cannot figure out how to programmatically transfer the file when it is created.
My job position is just data analyze (Not programming)
So, the lack of background programming knowledge is my big concern
If there is a way to trigger the scp to copy the file when it is created, please let me know.
You could use inotifywait to monitor the directory and run a command every time a file is created in the directory. In this case, you would fire off the scp command. IF you have it set up to not prompt for the password, you should be all set.
inotifywait -mrq -e CREATE --format %w%f /path/to/dir | while read FILE; do scp "$FILE"analysis_server:/path/on/anaylsis/server/; done
You can find out more about inotifywait at http://techarena51.com/index.php/inotify-tools-example/
Here is my problem,
In Windows I am making a zip file in which there is a text .sh file which is supposed to be executed in Linux.
The user on the other end opens the zip file in Linux and tries to execute the .sh file but the execute permission is gone. So the user has to do it manually ( like explained here:add execute permission.
How can I in Windows make the .sh executable and add it to a zip file so that when the zip file opens in linux the .sh file still retains its execute permission ( so that user doesn't have to do it manually)
As far as I know the permission system in Linux is set up in such a way to prevent exactly what you are trying to accomplish.
I think the best you can do is to give your Linux user a custom unzip one-liner to run on the prompt:
unzip zip_name.zip && chmod +x script_name.sh
If there are multiple scripts that you need to give execute permission to, write a grant_perms.sh as follows:
#!/bin/bash
# file: grant_perms.sh
chmod +x script_1.sh
chmod +x script_2.sh
...
chmod +x script_n.sh
(You can put the scripts all on one line for chmod, but I found separate lines easier to work with in vim and with shell script commands.)
And now your unzip one-liner becomes:
unzip zip_name.zip && source grant_perms.sh
Note that since you are using source to run grant_perms.sh, it doesn't need execute permission
The ZIP file format does allow to store the permission bits, but Windows programs normally ignore it.
The zip utility on Cygwin however does preserve the x bit, just like it does on Linux.
If you do not want to use Cygwin, you can take a source code and tweak it so that all *.sh files get the executable bit set.
Or write a script like explained here
This is possible using the Info-Zip open-source Zip utilities. If unzip is run with the -X parameter, it will attempt to preserve the original permissions. If the source filesystem was NTFS and the destination is a Unix one, it will attempt to translate from one to the other. I do not have a Windows system available right now to test the translation, so you will have to experiment with which group needs to be awarded execute permissions. It'll be something like "Users" or "Any user"
Use my windows command line utility zip_exec.zip to set the executable flag for linux/unix and mac (tested on files created with Windows Explorer and 7zip). The cpp source is also available. I searched the internet a lot before making my own utility. It can be modified to set any file attribute.
This is not possible. Linux permissions and windows permissions do not translate. They are machine specific. It would be a security hole to allow permissions to be set on files before they even arrive on the target system.
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.