MOUNT(8) UNIX Programmer's Manual MOUNT(8) NAME mount - mount file systems SYNOPSIS mount [ -adfruvw ] [ -t _u_f_s | _e_x_t_e_r_n_a_l__t_y_p_e ] mount [ -dfruvw ] _s_p_e_c_i_a_l | _n_o_d_e mount [ -dfruvw ] [ -o _o_p_t_i_o_n_s ] [ -t _u_f_s | _e_x_t_e_r_n_a_l__t_y_p_e ] _s_p_e_c_i_a_l _n_o_d_e DESCRIPTION The mount command calls the mount(2) system call to prepare and graft a _s_p_e_c_i_a_l _d_e_v_i_c_e on to the file system tree at the point _n_o_d_e. If either _s_p_e_c_i_a_l or _n_o_d_e are not provided, the appropriate information is taken from the fstab(5) file. The system maintains a list of currently mounted file sys- tems. If no arguments are given to mount, this list is printed. The options are as follows: -a Causes everything to be done except for the actual system call. This option is useful in conjunction with the -v flag to determine what the mount command is trying to do. -f Forces the revocation of write access when trying to downgrade a filesystem mount status from read- write to read-only. For 2.11BSD this flag is currently not implemented. -o Options are specified with a -o flag followed by a comma separated string of options. The following options are available: async All I/O to the file system should be done asynchronously. This is a dangerous flag to and should not be used unless system should your system crash. force The same as -f; forces the revocation of write access when trying to downgrade a filesystem mount status from read-write to read-only. This is not (and likely never will be) supported in 2.11BSD. Printed 11/24/99 November 16, 1996 1 MOUNT(8) UNIX Programmer's Manual MOUNT(8) noaccesstime File access times are not updated. This is a performance optimization for read-only, short-lived data, e.g., news. noauto This filesystem should be skipped when mount is run with the -a flag. na Same as noauto. nodev Do not interpret character or block spe- cial devices on the file system. This option is useful for a server that has file systems containing special devices for architectures other than its own. noexec Do not allow execution of any binaries on the mounted file system. This option is useful for a server that has file systems containing binaries for archi- tectures other than its own. nosuid Do not allow set-user-identifier or set-group-identifier bits to take effect. rdonly The same as -r; mount the file system read-only (even the super-user may not write it). sync All I/O to the file system should be done synchronously. update The same as -u; indicate that the status of an already mounted file system should be changed. Any additional options specific to a filesystem type that is not one of the internally known types (see the -t option) may be passed as a comma separated list; these options are distinguished by a leading - (dash). Options that take a value are specified using the syntax -option=value. At present no 2.11BSD mount options use the following form, the example has been retained for illustra- tive purposes only. For example, the mount com- mand: mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp Printed 11/24/99 November 16, 1996 2 MOUNT(8) UNIX Programmer's Manual MOUNT(8) causes mount to execute the equivalent of: /sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp -r The file system is to be mounted read-only. Mount the file system read-only (even the super-user may not write it). The same as the ``rdonly'' argument to the -o option. -t "_u_f_s | _e_x_t_e_r_n_a_l _t_y_p_e" The argument following the -t is used to indi- cate the file system type. The type _u_f_s is the default. _U_f_s is also the only value supported by 2.11BSD other than _s_w_a_p. Thus the -t will rarely be used. The -t option can be used to indicate that the actions should only be taken on filesystems of the specified type. More than one type may be specified in a comma separated list. The list of filesystem types can be pre- fixed with ``no'' to specify the filesystem types for which action should _n_o_t be taken. For example, the mount command: mount -a -t nonfs,mfs mounts all filesystems except those of type NFS and MFS. If the type is not one of the internally known types, mount will attempt to execute a program in /_s_b_i_n/_m_o_u_n_t__X_X_X where _X_X_X is replaced by the type name. For example, mfs filesystems are mounted by the program /_s_b_i_n/_m_o_u_n_t__m_f_s. -u The -u flag indicates that the status of an already mounted file system should be changed. Any of the options discussed above (the -o option) may be changed; also a file system can be changed from read-only to read-write or vice versa. An attempt to change from read-write to read-only will fail if any files on the filesys- tem are currently open for writing unless the -f flag is also specified. This is currently not implemented in 2.11BSD. The ability to change the flags (nodev, nosuid, etc) is however sup- ported. The set of options is determined by first extracting the options for the file system from the _f_s_t_a_b table, then applying any options specified by the -o argument, and finally apply- ing the -r or -w option. Printed 11/24/99 November 16, 1996 3 MOUNT(8) UNIX Programmer's Manual MOUNT(8) -v Verbose mode. -w The file system object is to be read and write. FILES /etc/fstab file system table SEE ALSO mount(2), fstab(5), umount(8) BUGS It is possible for a corrupted file system to cause a crash. mount and this manpage were ported from 4.4BSD-Lite to 2.11BSD to gain the ability to set the various flags such as nodev, nosuid and so on. Multiple filesystem types are not supported and several of the options and flags are not implemented. HISTORY A mount command appeared in Version 6 AT&T UNIX. Printed 11/24/99 November 16, 1996 4