如何设置用户的权限，以便它可以执行bash脚本来读取其他用户的文件？

Question

I have a web server on a Debian machine and another Debian machine which runs an application. I want to have the web user call a bash script that returns some info for the php to process.

I have already generated ssh keys and paired my web user (www-data) with a user on the target machine (usr_scripts) and I have the following command which runs the bash script on the target machine:

ssh -o UserKnownHostsFile=/path/to/known_hosts -i /path/to/rsa/key usr_scripts@targetMachine scriptToReadFiles.sh

The scriptToReadFiles.sh is a plain bash script that uses cat to output some info from different files ( cat /path/to/mainFolder/Folder1/File1 ) and I have a function in my php that takes the output and generates a report.

My problem now is that usr_scripts has insufficient permissions to read the files I need. All the files are inside different folders and they have different owners (as the application uses multiple users for different tasks) like that:

mainFolder
 |- Folder 1 (owner: user1)
 |   |- File 1 (owner: user1)
 |   |- File 2 (owner: user1)
 |
 |- Folder 2 (owner: user2)
     |- File 1 (owner: user2)
     |- File 2 (owner: user2)
     |- File 3 (owner: user2)

Users user1, user2 etc. are dynamically generated from the application (to whose source code I have no access), they are generated as needed, they don't belong to a certain group and they mustn't have access to other files outside of their designated home folder.

How should I set up my use_scripts user's privileges so it can read those files?

Answer 1

you can use chmod to change the modes of the current files and umask to change the future files. here is a link to some info for umask http://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.html