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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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LS(1P) POSIX Programmer's Manual LS(1P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
ls — list directory contents
ls [-ikqrs] [-glno] [-A|-a] [-C|-m|-x|-1] \
[-F|-p] [-H|-L] [-R|-d] [-S|-f|-t] [-c|-u] [file...]
For each operand that names a file of a type other than directory
or symbolic link to a directory, ls shall write the name of the
file as well as any requested, associated information. For each
operand that names a file of type directory, ls shall write the
names of files contained within the directory as well as any
requested, associated information. Filenames beginning with a
<period> ('.') and any associated information shall not be
written out unless explicitly referenced, the -A or -a option is
supplied, or an implementation-defined condition causes them to be
written. If one or more of the -d, -F, or -l options are
specified, and neither the -H nor the -L option is specified, for
each operand that names a file of type symbolic link to a
directory, ls shall write the name of the file as well as any
requested, associated information. If none of the -d, -F, or -l
options are specified, or the -H or -L options are specified, for
each operand that names a file of type symbolic link to a
directory, ls shall write the names of files contained within the
directory as well as any requested, associated information. In
each case where the names of files contained within a directory
are written, if the directory contains any symbolic links then ls
shall evaluate the file information and file type to be those of
the symbolic link itself, unless the -L option is specified.
If no operands are specified, ls shall behave as if a single
operand of dot ('.') had been specified. If more than one operand
is specified, ls shall write non-directory operands first; it
shall sort directory and non-directory operands separately
according to the collating sequence in the current locale.
Whenever ls sorts filenames or pathnames according to the
collating sequence in the current locale, if this collating
sequence does not have a total ordering of all characters (see the
Base Definitions volume of POSIX.1‐2017, Section 7.3.2,
LC_COLLATE), then any filenames or pathnames that collate equally
should be further compared byte-by-byte using the collating
sequence for the POSIX locale.
The ls utility shall detect infinite loops; that is, entering a
previously visited directory that is an ancestor of the last file
encountered. When it detects an infinite loop, ls shall write a
diagnostic message to standard error and shall either recover its
position in the hierarchy or terminate.
The ls utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
-A Write out all directory entries, including those whose
names begin with a <period> ('.') but excluding the
entries dot and dot-dot (if they exist).
-C Write multi-text-column output with entries sorted down
the columns, according to the collating sequence. The
number of text columns and the column separator
characters are unspecified, but should be adapted to the
nature of the output device. This option disables long
format output.
-F Do not follow symbolic links named as operands unless
the -H or -L options are specified. Write a <slash>
('/') immediately after each pathname that is a
directory, an <asterisk> ('*') after each that is
executable, a <vertical-line> ('|') after each that is a
FIFO, and an at-sign ('@') after each that is a symbolic
link. For other file types, other symbols may be
written.
-H Evaluate the file information and file type for symbolic
links specified on the command line to be those of the
file referenced by the link, and not the link itself;
however, ls shall write the name of the link itself and
not the file referenced by the link.
-L Evaluate the file information and file type for all
symbolic links (whether named on the command line or
encountered in a file hierarchy) to be those of the file
referenced by the link, and not the link itself;
however, ls shall write the name of the link itself and
not the file referenced by the link. When -L is used
with -l, write the contents of symbolic links in the
long format (see the STDOUT section).
-R Recursively list subdirectories encountered. When a
symbolic link to a directory is encountered, the
directory shall not be recursively listed unless the -L
option is specified. The use of -R with -d or -f
produces unspecified results.
-S Sort with the primary key being file size (in decreasing
order) and the secondary key being filename in the
collating sequence (in increasing order).
-a Write out all directory entries, including those whose
names begin with a <period> ('.').
-c Use time of last modification of the file status
information (see the Base Definitions volume of
POSIX.1‐2017, sys_stat.h(0p)) instead of last
modification of the file itself for sorting (-t) or
writing (-l).
-d Do not follow symbolic links named as operands unless
the -H or -L options are specified. Do not treat
directories differently than other types of files. The
use of -d with -R or -f produces unspecified results.
-f List the entries in directory operands in the order they
appear in the directory. The behavior for non-directory
operands is unspecified. This option shall turn on -a.
When -f is specified, any occurrences of the -r, -S, and
-t options shall be ignored and any occurrences of the
-A, -g, -l, -n, -o, and -s options may be ignored. The
use of -f with -R or -d produces unspecified results.
-g Turn on the -l (ell) option, but disable writing the
file's owner name or number. Disable the -C, -m, and -x
options.
-i For each file, write the file's file serial number (see
stat() in the System Interfaces volume of POSIX.1‐2017).
-k Set the block size for the -s option and the per-
directory block count written for the -l, -n, -s, -g,
and -o options (see the STDOUT section) to 1024 bytes.
-l (The letter ell.) Do not follow symbolic links named as
operands unless the -H or -L options are specified.
Write out in long format (see the STDOUT section).
Disable the -C, -m, and -x options.
-m Stream output format; list pathnames across the page,
separated by a <comma> character followed by a <space>
character. Use a <newline> character as the list
terminator and after the separator sequence when there
is not room on a line for the next list entry. This
option disables long format output.
-n Turn on the -l (ell) option, but when writing the file's
owner or group, write the file's numeric UID or GID
rather than the user or group name, respectively.
Disable the -C, -m, and -x options.
-o Turn on the -l (ell) option, but disable writing the
file's group name or number. Disable the -C, -m, and -x
options.
-p Write a <slash> ('/') after each filename if that file
is a directory.
-q Force each instance of non-printable filename characters
and <tab> characters to be written as the <question-
mark> ('?') character. Implementations may provide this
option by default if the output is to a terminal device.
-r Reverse the order of the sort to get reverse collating
sequence oldest first, or smallest file size first
depending on the other options given.
-s Indicate the total number of file system blocks consumed
by each file displayed. If the -k option is also
specified, the block size shall be 1024 bytes;
otherwise, the block size is implementation-defined.
-t Sort with the primary key being time modified (most
recently modified first) and the secondary key being
filename in the collating sequence. For a symbolic
link, the time used as the sort key is that of the
symbolic link itself, unless ls is evaluating its file
information to be that of the file referenced by the
link (see the -H and -L options).
-u Use time of last access (see the Base Definitions volume
of POSIX.1‐2017, sys_stat.h(0p)) instead of last
modification of the file for sorting (-t) or writing
(-l).
-x The same as -C, except that the multi-text-column output
is produced with entries sorted across, rather than
down, the columns. This option disables long format
output.
-1 (The numeric digit one.) Force output to be one entry
per line. This option does not disable long format
output. (Long format output is enabled by -g, -l (ell),
-n, and -o; and disabled by -C, -m, and -x.)
If an option that enables long format output (-g, -l (ell), -n,
and -o is given with an option that disables long format output
(-C, -m, and -x), this shall not be considered an error. The last
of these options specified shall determine whether long format
output is written.
If -R, -d, or -f are specified, the results of specifying these
mutually-exclusive options are specified by the descriptions of
these options above. If more than one of any of the other options
shown in the SYNOPSIS section in mutually-exclusive sets are
given, this shall not be considered an error; the last option
specified in each set shall determine the output.
Note that if -t is specified, -c and -u are not only mutually-
exclusive with each other, they are also mutually-exclusive with
-S when determining sort order. But even if -S is specified after
all occurrences of -c, -t, and -u, the last use of -c or -u
determines the timestamp printed when producing long format
output.
The following operand shall be supported:
file A pathname of a file to be written. If the file
specified is not found, a diagnostic message shall be
output on standard error.
Not used.
None.
The following environment variables shall affect the execution of
ls:
COLUMNS Determine the user's preferred column position width for
writing multiple text-column output. If this variable
contains a string representing a decimal integer, the ls
utility shall calculate how many pathname text columns
to write (see -C) based on the width provided. If
COLUMNS is not set or invalid, an implementation-defined
number of column positions shall be assumed, based on
the implementation's knowledge of the output device. The
column width chosen to write the names of files in any
given directory shall be constant. Filenames shall not
be truncated to fit into the multiple text-column
output.
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization variables used to determine the
values of locale categories.)
LC_ALL If set to a non-empty string value, override the values
of all the other internationalization variables.
LC_COLLATE
Determine the locale for character collation information
in determining the pathname collation sequence.
LC_CTYPE Determine the locale for the interpretation of sequences
of bytes of text data as characters (for example,
single-byte as opposed to multi-byte characters in
arguments) and which characters are defined as printable
(character class print).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
LC_TIME Determine the format and contents for date and time
strings written by ls.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
TZ Determine the timezone for date and time strings written
by ls. If TZ is unset or null, an unspecified default
timezone shall be used.
Default.
The default format shall be to list one entry per line to standard
output; the exceptions are to terminals or when one of the -C, -m,
or -x options is specified. If the output is to a terminal, the
format is implementation-defined.
When -m is specified, the format used for the last element of the
list shall be:
"%s\n", <filename>
The format used for each other element of the list shall be:
"%s,%s", <filename>, <separator>
where, if there is not room for the next element of the list to
fit within the current line length, <separator> is a string
containing an optional <space> character and a mandatory <newline>
character; otherwise it is a single <space> character.
If the -i option is specified, the file's file serial number (see
the Base Definitions volume of POSIX.1‐2017, sys_stat.h(0p)) shall
be written in the following format before any other output for the
corresponding entry:
%u ", <file serial number>
If the -l option is specified, the following information shall be
written for files other than character special and block special
files:
"%s %u %s %s %u %s %s\n", <file mode>, <number of links>,
<owner name>, <group name>, <size>, <date and time>,
<pathname>
If the -l option is specified, the following information shall be
written for character special and block special files:
"%s %u %s %s %s %s %s\n", <file mode>, <number of links>,
<owner name>, <group name>, <device info>, <date and time>,
<pathname>
In both cases if the file is a symbolic link and the -L option is
also specified, this information shall be for the file resolved
from the symbolic link, except that the <pathname> field shall
contain the pathname of the symbolic link itself. If the file is a
symbolic link and the -L option is not specified, this information
shall be about the link itself and the <pathname> field shall be
of the form:
"%s -> %s", <pathname of link>, <contents of link>
The -n, -g, and -o options use the same format as -l, but with
omitted items and their associated <blank> characters. See the
OPTIONS section.
In both the preceding -l forms, if <owner name> or <group name>
cannot be determined, or if -n is given, they shall be replaced
with their associated numeric values using the format %u.
The <size> field shall contain the value that would be returned
for the file in the st_size field of struct stat (see the Base
Definitions volume of POSIX.1‐2017, sys_stat.h(0p)). Note that
for some file types this value is unspecified.
The <device info> field shall contain implementation-defined
information associated with the device in question.
The <date and time> field shall contain the appropriate date and
timestamp of when the file was last modified. In the POSIX locale,
the field shall be the equivalent of the output of the following
date command:
date "+%b %e %H:%M"
if the file has been modified in the last six months, or:
date "+%b %e %Y"
(where two <space> characters are used between %e and %Y) if the
file has not been modified in the last six months or if the
modification date is in the future, except that, in both cases,
the final <newline> produced by date shall not be included and the
output shall be as if the date command were executed at the time
of the last modification date of the file rather than the current
time. When the LC_TIME locale category is not set to the POSIX
locale, a different format and order of presentation of this field
may be used.
If the pathname was specified as a file operand, it shall be
written as specified.
The file mode written under the -l, -n, -g, and -o options shall
consist of the following format:
"%c%s%s%s%s", <entry type>, <owner permissions>,
<group permissions>, <other permissions>,
<optional alternate access method flag>
The <optional alternate access method flag> shall be the empty
string if there is no alternate or additional access control
method associated with the file; otherwise, it shall be a string
containing a single printable character that is not a <blank>.
The <entry type> character shall describe the type of file, as
follows:
d Directory.
b Block special file.
c Character special file.
l (ell) Symbolic link.
p FIFO.
- Regular file.
Implementations may add other characters to this list to represent
other implementation-defined file types.
The next three fields shall be three characters each:
<owner permissions>
Permissions for the file owner class (see the Base
Definitions volume of POSIX.1‐2017, Section 4.5, File Access
Permissions).
<group permissions>
Permissions for the file group class.
<other permissions>
Permissions for the file other class.
Each field shall have three character positions:
1. If 'r', the file is readable; if '-', the file is not
readable.
2. If 'w', the file is writable; if '-', the file is not
writable.
3. The first of the following that applies:
S If in <owner permissions>, the file is not executable
and set-user-ID mode is set. If in <group permissions>,
the file is not executable and set-group-ID mode is set.
s If in <owner permissions>, the file is executable and
set-user-ID mode is set. If in <group permissions>, the
file is executable and set-group-ID mode is set.
T If in <other permissions> and the file is a directory,
search permission is not granted to others, and the
restricted deletion flag is set.
t If in <other permissions> and the file is a directory,
search permission is granted to others, and the
restricted deletion flag is set.
x The file is executable or the directory is searchable.
- None of the attributes of 'S', 's', 'T', 't', or 'x'
applies.
Implementations may add other characters to this list for the
third character position. Such additions shall, however, be
written in lowercase if the file is executable or searchable,
and in uppercase if it is not.
If any of the -l, -n, -s, -g, or -o options is specified, each
list of files within the directory shall be preceded by a status
line indicating the number of file system blocks occupied by files
in the directory in 512-byte units if the -k option is not
specified, or 1024-byte units if the -k option is specified,
rounded up to the next integral number of units, if necessary. In
the POSIX locale, the format shall be:
"total %u\n", <number of units in the directory>
If more than one directory, or a combination of non-directory
files and directories are written, either as a result of
specifying multiple operands, or the -R option, each list of files
within a directory shall be preceded by:
"\n%s:\n", <directory name>
If this string is the first thing to be written, the first
<newline> shall not be written. This output shall precede the
number of units in the directory.
If the -s option is given, each file shall be written with the
number of blocks used by the file. Along with -C, -1, -m, or -x,
the number and a <space> shall precede the filename; with -l, -n,
-g, or -o, they shall precede each line describing a file.
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Default.
The following sections are informative.
Many implementations use the <equals-sign> ('=') to denote sockets
bound to the file system for the -F option. Similarly, many
historical implementations use the 's' character to denote sockets
as the entry type characters for the -l option.
It is difficult for an application to use every part of the file
modes field of ls -l in a portable manner. Certain file types and
executable bits are not guaranteed to be exactly as shown, as
implementations may have extensions. Applications can use this
field to pass directly to a user printout or prompt, but actions
based on its contents should generally be deferred, instead, to
the test utility.
The output of ls (with the -l and related options) contains
information that logically could be used by utilities such as
chmod and touch to restore files to a known state. However, this
information is presented in a format that cannot be used directly
by those utilities or be easily translated into a format that can
be used. A character has been added to the end of the permissions
string so that applications at least have an indication that they
may be working in an area they do not understand instead of
assuming that they can translate the permissions string into
something that can be used. Future versions or related documents
may define one or more specific characters to be used based on
different standard additional or alternative access control
mechanisms.
As with many of the utilities that deal with filenames, the output
of ls for multiple files or in one of the long listing formats
must be used carefully on systems where filenames can contain
embedded white space. Systems and system administrators should
institute policies and user training to limit the use of such
filenames.
The number of disk blocks occupied by the file that it reports
varies depending on underlying file system type, block size units
reported, and the method of calculating the number of blocks. On
some file system types, the number is the actual number of blocks
occupied by the file (counting indirect blocks and ignoring holes
in the file); on others it is calculated based on the file size
(usually making an allowance for indirect blocks, but ignoring
holes).
An example of a small directory tree being fully listed with ls
-laRF a in the POSIX locale:
total 11
drwxr-xr-x 3 fox prog 64 Jul 4 12:07 ./
drwxrwxrwx 4 fox prog 3264 Jul 4 12:09 ../
drwxr-xr-x 2 fox prog 48 Jul 4 12:07 b/
-rwxr--r-- 1 fox prog 572 Jul 4 12:07 foo*
a/b:
total 4
drwxr-xr-x 2 fox prog 48 Jul 4 12:07 ./
drwxr-xr-x 3 fox prog 64 Jul 4 12:07 ../
-rw-r--r-- 1 fox prog 700 Jul 4 12:07 bar
Some historical implementations of the ls utility show all entries
in a directory except dot and dot-dot when a superuser invokes ls
without specifying the -a option. When ``normal'' users invoke ls
without specifying -a, they should not see information about any
files with names beginning with a <period> unless they were named
as file operands.
Implementations are expected to traverse arbitrary depths when
processing the -R option. The only limitation on depth should be
based on running out of physical storage for keeping track of
untraversed directories.
The -1 (one) option was historically found in BSD and BSD-derived
implementations only. It is required in this volume of
POSIX.1‐2017 so that conforming applications might ensure that
output is one entry per line, even if the output is to a terminal.
The -S option was added in Issue 7, but had been provided by
several implementations for many years. The description given in
the standard documents historic practice, but does not match much
of the documentation that described its behavior. Historical
documentation typically described it as something like:
-S Sort by size (largest size first) instead of by name.
Special character devices (listed last) are sorted by
name.
even though the file type was never considered when sorting the
output. Character special files do typically sort close to the
end of the list because their file size on most implementations is
zero. But they are sorted alphabetically with any other files that
happen to have the same file size (zero), not sorted separately
and added to the end.
This volume of POSIX.1‐2017 is frequently silent about what
happens when mutually-exclusive options are specified. Except for
-R, -d, and -f, the ls utility is required to accept multiple
options from each mutually-exclusive option set without treating
them as errors and to use the behavior specified by the last
option given in each mutually-exclusive set. Since ls is one of
the most aliased commands, it is important that the implementation
perform intuitively. For example, if the alias were:
alias ls="ls -C"
and the user typed ls -1 (one), single-text-column output should
result, not an error.
The -g, -l (ell), -n, and -o options are not mutually-exclusive
options. They all enable long format output. They work together to
determine whether the file's owner is written (no if -g is
present), file's group is written (no if -o is present), and if
the file's group or owner is written whether it is written as the
name (default) or a string representation of the UID or GID number
(if -n is present). The -C, -m, -x, and -1 (one) are mutually-
exclusive options and the first three of these disable long format
output. The -1 (one) option does not directly change whether or
not long format output is enabled, but by overriding -C, -m, and
-x, it can re-enable long format output that had been disabled by
one of these options.
Earlier versions of this standard did not describe the BSD -A
option (like -a, but dot and dot-dot are not written out). It has
been added due to widespread implementation.
Implementations may make -q the default for terminals to prevent
trojan horse attacks on terminals with special escape sequences.
This is not required because:
* Some control characters may be useful on some terminals; for
example, a system might write them as "\001" or "^A".
* Special behavior for terminals is not relevant to applications
portability.
An early proposal specified that the
<optional alternate access method flag> had to be '+' if there was
an alternate access method used on the file or <space> if there
was not. This was changed to be <space> if there is not and a
single printable character if there is. This was done for three
reasons:
1. There are historical implementations using characters other
than '+'.
2. There are implementations that vary this character used in
that position to distinguish between various alternate access
methods in use.
3. The standard developers did not want to preclude future
specifications that might need a way to specify more than one
alternate access method.
Nonetheless, implementations providing a single alternate access
method are encouraged to use '+'.
Earlier versions of this standard did not have the -k option,
which meant that the -s option could not be used portably as its
block size was implementation-defined, and the units used to
specify the number of blocks occupied by files in a directory in
an ls -l listing were fixed as 512-byte units. The -k option has
been added to provide a way for the -s option to be used portably,
and for consistency it also changes the aforementioned units from
512-byte to 1024-byte.
The <date and time> field in the -l format is specified only for
the POSIX locale. As noted, the format can be different in other
locales. No mechanism for defining this is present in this volume
of POSIX.1‐2017, as the appropriate vehicle is a messaging system;
that is, the format should be specified as a ``message''.
Allowing -f to ignore the -A, -g, -l, -n, -o, and -s options may
be removed in a future version.
A future version of this standard may require that if the
collating sequence for the current locale does not have a total
ordering of all characters, any filenames or pathnames that
collate equally are further compared byte-by-byte using the
collating sequence for the POSIX locale.
chmod(1p), find(1p)
The Base Definitions volume of POSIX.1‐2017, Section 7.3.2,
LC_COLLATE, Section 4.5, File Access Permissions, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines,
sys_stat.h(0p)
The System Interfaces volume of POSIX.1‐2017, fstatat(3p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics Engineers,
Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard,
the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 LS(1P)
Pages that refer to this page: chmod(1p), du(1p), file(1p), mailx(1p), pax(1p)
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