/proc/filesystems: Explanation & Insights

Information about supported filesystems

/proc/filesystems is a virtual file that provides information about the filesystems that are currently supported by the Linux kernel. Each supported filesystem has a corresponding entry in /proc/filesystems.

When you run the cat /proc/filesystems command, it will display a list of all the filesystems that the kernel supports, along with their type and other relevant information.

Here's an example output of the command:

nodev   sysfs
nodev   rootfs
nodev   ramfs
nodev   bdev
nodev   proc
nodev   cpuset
nodev   cgroup
nodev   cgroup2
nodev   tmpfs
nodev   devtmpfs
nodev   debugfs
nodev   tracefs
nodev   securityfs
nodev   sockfs
nodev   bpf
nodev   configfs
nodev   dax
nodev   hugetlbfs
nodev   zsmalloc
nodev   overlay
nodev   mnt-nfs

Each line represents a filesystem type. The first column specifies whether the filesystem is a block device (bdev) or a node device (nodev). The second column is the name of the filesystem.

For example, sysfs is a virtual filesystem that provides information about the system's hardware and software configuration. ramfs is a temporary filesystem that resides in memory, and proc is a virtual filesystem that provides information about running processes.

In summary, /proc/filesystems provides a convenient way to see the filesystems that are currently supported by the Linux kernel, and it can be useful when troubleshooting issues related to filesystems.