9.2. Creating the /etc/fstab File

The /etc/fstab file is used by some programs to determine where file systems are to be mounted by default, in which order, and which must be checked (for integrity errors) prior to mounting. Create a new file systems table like this:

cat > ${CLFS}/etc/fstab << "EOF"
# Begin /etc/fstab

# file system  mount-point  type   options          dump  fsck
#                                                         order

proc           /proc        proc   defaults         0     0
sysfs          /sys         sysfs  defaults         0     0
devpts         /dev/pts     devpts gid=4,mode=620   0     0
shm            /dev/shm     tmpfs  defaults         0     0
# End /etc/fstab
EOF

For details on the six fields in this file, see man 5 fstab.

The /dev/shm mount point for tmpfs is included to allow enabling POSIX-shared memory. The kernel must have the required support built into it for this to work (more about this is in the next section). Please note that very little software currently uses POSIX-shared memory. Therefore, consider the /dev/shm mount point optional. For more information, see Documentation/filesystems/tmpfs.txt in the kernel source tree.