The /proc/ directory is a virtual file system that contains information about the system and the
processes running on it. It is not a conventional file system that stores files on a disk, but rather a
dynamic view of the kernel’s data structures. One of the features of the /proc/ directory is that it
contains one subdirectory for each process running on the system, which is named after the process
ID (PID). For example, the subdirectory /proc/1/ contains information about the process with PID 1,
which is usually the init process. The process subdirectories contain various files that provide
information about the process, such as its status, memory usage, open files, environment variables,
command line arguments, and more. The /proc/ directory also contains a symbolic link called ‘self’,
which points to the process that is accessing the /proc/ file system. Therefore, the correct answer is
D. One directory per running process.
The other options are incorrect because:
A . One directory per installed program. This is not true, as the /proc/ directory does not contain
information about installed programs, but only about running processes. Installed programs are
usually stored in other directories, such as /bin/, /usr/bin/, /opt/, etc.
B . One device file per hardware device. This is not true, as the /proc/ directory does not contain
device files, but only virtual files that represent kernel data. Device files are usually stored in the
/dev/ directory, which is another special file system that provides access to hardware devices.
C . One file per existing user account. This is not true, as the /proc/ directory does not contain
information about user accounts, but only about processes. User accounts are usually stored in the
/etc/ directory, which contains configuration files, such as /etc/passwd/ and /etc/shadow/, that
define the users and their passwords.
E . One log file per running service. This is not true, as the /proc/ directory does not contain log files,
but only information files. Log files are usually stored in the /var/log/ directory, which contains
various files that record the activities of the system and the services.
Reference:
The /proc Filesystem — The Linux Kernel documentation
A Beginner’s Guide to the /proc File System in Linux - Tecmint
Appendix E. The proc File System Red Hat Enterprise Linux 6 | Red Hat …
Chapter 5. The proc File System Red Hat Enterprise Linux 4 | Red Hat …
proc file system in Linux - GeeksforGeeks
