Refreshing a file’s date TOUCH pathname1 [pathname2] ... The TOUCH command changes the modification time/date in one or more files’ or directories’ directory entries to the current system time and date. This can be very handy when arranging backup copies of current files, or for programmers who need to keep file dates consistent. Changing file attributes FILEMODE 0 mask file1 [file2] ... Clear attribute bits FILEMODE 1 mask file1 [file2] ... Set attribute bits The FILEMODE command allows the setting and clearing of a file or directory’s attribute bits. These bits are displayed as part of the directory entry, in the order DALRWXS . Each disk file has 16 attribute bits in its directory entry.
Ten are currently defined: Bit Mask Usage 0 A $0001 Backup bit: the file is backed up 1 D $0002 Directory bit: the directory entry refers to a directory 2 L $0004 Locked bit: the file is locked (read - only) 3 R $0008 Read permission: open for users other than 0 4 W $0010 Write permission: open to users other than 0 5 X $0020 Execute: available to users other than 0 6 S $0040 Symbolic link: multiple names for a file 7 $0080 File with address in directory entry 8 $0100 Hidden file, not shown by dir 9 $0200 Boring bit, don’t bother to back up Attribute bits are set using the FILEMODE 1 mask filenames command. The first argument (1) specifies that attributes are to be set on.
The MASK is a bitmask of those attributes which are to be set; this is obtained by logically ORing the desired bits together. A list of the files to be altered follows the MASK. Attribute bits are cleared using the FILEMODE 0 mask filenames command. The BACKUP bit in a file’s attribute field indicates that the file has been backed up somewhere. The DIRECTORY bit indicates that the directory entry refers to a sub-directory, not to a file. If the LOCKED bit is set the file cannot be altered (until you unlock it). For obvious reasons, FILEMODE ignores any instruction to alter the directory bit, or the file address bit, since you don’t really want to alter them.
The read, write and execute (RWX) bits apply only to users other than user 0. User 0 can use files regardless of these three bits. However, if user 1 (etc) tries to, say, read a file without a read (R) permission, they will get an error message Cannot open .... Permission denied. Normally, you are always (by default) User Page 68 User Tutorial Manual 1616/OS Commands