ls(1)
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NAME

ls - list contents of directory

SYNOPSIS

ls [-RaAdCLHxmlnogrtucpFbqisf] [names]

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 is to list one entry per line, the -C and -x options enable multi-column formats, and the -m option 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.

-A
Like -a except it does not list the . and .. directories.

-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.

-C
Multi-column output with entries sorted down the columns.

-L
If the file is a symbolic link, list the file that the link references.

-H
If the file is a symbolic link, list the file itself. This is the default behavior, except for a symbolic link to a directory in the absence of the -l option, in which case the -L behavior is used by default. -H and -L cancel one another in command line order.

-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 will instead contain the major and minor device numbers rather than a size.

-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 -u 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 the name of each file that is a directory.

-F
Put a slash (/) after the name of each file that is a directory, put an asterisk (*) after the name of each file that is executable, put a commercial at sign (@) after the name of each file that is a symbolic link and put an equals sign (=) after the name of each file that is a AF_UNIX address family socket.

-b
Force printing of non-printable characters to be in the octal \\ddd notation.

-q
Force printing of non-printable characters in file names as the character question mark (?).

-i
For each file, print the i-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.

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;
b
the entry is a block special file;
c
the entry is a character special file;
l
the entry is a symbolic link;
p
the entry is a fifo (a.k.a. "named pipe") special file;
s
the entry is a AF_UNIX address family socket;
-
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

This horizontal configuration provides a good deal of information. Reading from right to left, you see that the current directory holds one file, named "part2." Next, the last time that file's contents were modified was 9:42 A.M. on May 16. The file is moderately sized, containing 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." Finally, the row of dash and letters tell you that user, group, and others have permissions to read, write, execute "part2."

The execute (x) symbol here occupies the third position of the threecharacter 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 will occur 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 bitstate)

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 stated at "login."

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 will print 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 will provide you with quite a bit of information including all files, including non-printing ones (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/lib/terminfo/?/*
terminal information database

SEE ALSO

 chmod(1), find(1).

BUGS

Unprintable characters in file names may confuse the columnar output options.

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