ls

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



PROLOG
       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
       ls — list directory contents

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

DESCRIPTION
       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.

OPTIONS
       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>)
                 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>) 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
       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
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       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.

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       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>) 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>).  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.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       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
       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
       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''.

FUTURE DIRECTIONS
       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.

SEE ALSO
       chmod, find

       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>

       The System Interfaces volume of POSIX.1‐2017, fstatat()

COPYRIGHT
       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)