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

LS(1P)                    POSIX Programmer's Manual                   LS(1P)

PROLOG         top

       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.

NAME         top

       ls — list directory contents

SYNOPSIS         top

       ls [−ikqrs] [−glno] [−A|−a] [−C|−m|−x|−1] \
           [−F|−p] [−H|−L] [−R|−d] [−S|−f|−t] [−c|−u] [file...]

DESCRIPTION         top

       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.

       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.

OPTIONS         top

       The ls utility shall conform to the Base Definitions volume of
       POSIX.1‐2008, 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.1‐2008, 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.1‐2008).

       −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.1‐2008, 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.

OPERANDS         top

       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.

STDIN         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       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.1‐2008, 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.

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       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.1‐2008, 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.1‐2008, 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.1‐2008, Section 4.4, 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.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       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).

EXAMPLES         top

       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

RATIONALE         top

       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.1‐2008
       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.1‐2008 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.1‐2008, as the appropriate vehicle is a messaging system; that
       is, the format should be specified as a ``message''.

FUTURE DIRECTIONS         top

       Allowing −f to ignore the −A, −g, −l, −n, −o, and −s options may be
       removed in a future version.

SEE ALSO         top

       chmod(1p), find(1p)

       The Base Definitions volume of POSIX.1‐2008, Section 4.4, File Access
       Permissions, Chapter 8, Environment Variables, Section 12.2, Utility
       Syntax Guidelines, sys_stat.h(0p)

       The System Interfaces volume of POSIX.1‐2008, fstatat(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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                 2013                              LS(1P)