ls(1) — USER COMMANDS
NAME
ls − list contents of directory
SYNOPSIS
ls [−RadLCxmlnogrtucpFbqisf1] [file . . . ]
DESCRIPTION
For each directory argument, ls lists the contents of the directory; for each file argument, ls repeats its name and any other information requested. The output is sorted alphabetically by default. When no argument is given, the current directory is listed. When several arguments are given, the arguments are first sorted appropriately, but file arguments appear before directories and their contents.
There are three major listing formats. The default format for output directed to a terminal is multi−column with entries sorted down the columns. The −1 option allows single column output and −m enables stream output format. In order to determine output formats for the −C, −x, and −m options, ls uses an environment variable, COLUMNS, to determine the number of character positions available on one output line. If this variable is not set, the terminfo(4) database is used to determine the number of columns, based on the environment variable TERM. If this information cannot be obtained, 80 columns are assumed.
The ls command has the following options:
−R Recursively list subdirectories encountered.
−a List all entries, including those that begin with a dot (.), which are normally not listed.
−d If an argument is a directory, list only its name (not its contents); often used with −l to get the status of a directory.
−L When listing status, if an argument is a symbolic link, list the status of the file or directory referenced by the link rather than that of the link itself.
−C Multi-column output with entries sorted down the columns. This is the default output format.
−x Multi-column output with entries sorted across rather than down the page.
−m Stream output format; files are listed across the page, separated by commas.
−l List in long format, giving mode, number of links, owner, group, size in bytes, and time of last modification for each file (see below). If the file is a special file, the size field instead contains the major and minor device numbers rather than a size. If the file is a symbolic link, the filename is printed followed by “->” and the pathname of the referenced file.
−n The same as −l, except that the owner’s UID and group’s GID numbers are printed, rather than the associated character strings.
−o The same as −l, except that the group is not printed.
−g The same as −l, except that the owner is not printed.
−r Reverse the order of sort to get reverse alphabetic or oldest first as appropriate.
−t Sort by time stamp (latest first) instead of by name. The default is the last modification time. (See −n and −c.)
−u Use time of last access instead of last modification for sorting (with the −t option) or printing (with the −l option).
−c Use time of last modification of the i-node (file created, mode changed, etc.) for sorting (−t) or printing (−l).
−p Put a slash (/) after each filename if the file is a directory.
−F Put a slash (/) after each filename if the file is a directory, an asterisk (∗) if the file is an executable, and an ampersand (@) if the file is a symbolic link.
−b Force printing of non-printable characters to be in the octal \ddd notation.
−q Force printing of non-printable characters in filenames as the character question mark (?).
−i For each file, print the i-node number in the first column of the report.
−s Give size in blocks, including indirect blocks, for each entry.
−f Force each argument to be interpreted as a directory and list the name found in each slot. This option turns off −l, −t, −s, and −r, and turns on −a; the order is the order in which entries appear in the directory.
−1 Print one entry per line of output.
The mode printed under the −l option consists of ten characters. The first character may be one of the following:
d the entry is a directory
l the entry is a symbolic link
b the entry is a block special file
c the entry is a character special file
m the entry is XENIX shared data (memory) file
p the entry is a fifo (a.k.a., named pipe) special file
s the entry is a XENIX semaphore
− the entry is an ordinary file
The next 9 characters are interpreted as three sets of three bits each. The first set refers to the owner’s permissions; the next to permissions of others in the user-group of the file; and the last to all others. Within each set, the three characters indicate permission to read, to write, and to execute the file as a program, respectively. For a directory, execute permission is interpreted to mean permission to search the directory for a specified file.
ls −l (the long list) prints its output as follows: −rwxrwxrwx 1 smith dev 10876 May 16 9:42 part2
Reading from right to left, you see that the current directory holds one file, named part2. The last time that file’s contents were modified was 9:42 A.M. on May 16. The file contains 10,876 characters, or bytes. The owner of the file, or the user, belongs to the group dev (perhaps indicating “development”), and his or her login name is smith. The number, in this case 1, indicates the number of links to file part2; see cp(1). Finally, the dash and letters tell you that user, group, and others have permissions to read, write, and execute part2.
The execute (x) symbol here occupies the third position of the three-character sequence. A − in the third position would have indicated a denial of execution permissions.
The permissions are indicated as follows:
r the file is readable
w the file is writable
x the file is executable
− the indicated permission is not granted
l mandatory locking occurs during access (the set-group-ID bit is on and the group execution bit is off)
s the set-user-ID or set-group-ID bit is on, and the corresponding user or group execution bit is also on
S undefined bit-state (the set-user-ID bit is on and the user execution bit is off)
t the 1000 (octal) bit, or sticky bit, is on [see chmod(1)], and execution is on
T the 1000 bit is turned on, and execution is off (undefined bit-state)
For user and group permissions, the third position is sometimes occupied by a character other than x or −. s also may occupy this position, referring to the state of the set-ID bit, whether it be the user’s or the group’s. The ability to assume the same ID as the user during execution is, for example, used during login when you begin as root but need to assume the identity of the user you login as.
In the case of the sequence of group permissions, l may occupy the third position. l refers to mandatory file and record locking. This permission describes a file’s ability to allow other files to lock its reading or writing permissions during access.
For others permissions, the third position may be occupied by t or T. These refer to the state of the sticky bit and execution permissions.
EXAMPLES
An example of a file’s permissions is:
−rwxr−−r−−
This describes a file that is readable, writable, and executable by the user and readable by the group and others.
Another example of a file’s permissions is:
−rwsr−xr−x
This describes a file that is readable, writable, and executable by the user, readable and executable by the group and others, and allows its user-ID to be assumed, during execution, by the user presently executing it.
Another example of a file’s permissions is:
−rw−rwl−−−
This describes a file that is readable and writable only by the user and the group and can be locked during access.
An example of a command line:
ls −a
This command prints the names of all files in the current directory, including those that begin with a dot (.), which normally do not print.
Another example of a command line:
ls −aisn
This command provides information on all files, including those that begin with a dot (a), the i-number—the memory address of the i-node associated with the file—printed in the left-hand column (i); the size (in blocks) of the files, printed in the column to the right of the i-numbers (s); finally, the report is displayed in the numeric version of the long list, printing the UID (instead of user name) and GID (instead of group name) numbers associated with the files.
When the sizes of the files in a directory are listed, a total count of blocks, including indirect blocks, is printed.
FILES
/etc/passwd user IDs for ls −l and ls −o
/etc/group group IDs for ls −l and ls −g
/usr/share/lib/terminfo/?/∗ terminal information database
INTERNATIONAL FUNCTIONS
ls can process directory and filenames containing characters from supplementary code sets. Multi-column output can be displayed correctly using the −C and −x options.
With the −b and −q options, ls considers all characters from supplementary code sets to be printable.
SEE ALSO
NOTES
In a Remote File Sharing (RFS) environment, you may not have the permissions that the output of the ls −l command leads you to believe.
Unprintable characters in filenames may confuse the columnar output options.
The total block count will be incorrect if there are hard links among the files.
— Essential Utilities