In Linux, you can find all the file descriptors used by a process by using the lsof command. The lsof (List Open Files) command lists information about files that are open by processes on a Linux system.
To find all the file descriptors used by a specific process, you can use the following command:
lsof -p <pid>
where <pid> is the process ID of the process you want to examine.
For example, if you want to find all the file descriptors used by the process with ID 12345, you can use the following command:
lsof -p 12345
This will display a list of all the open files and file descriptors used by the process with ID 12345.
Note that you need to run the lsof command as the root user or with sudo privileges in order to see the file descriptors used by all processes on the system.