1LS(P) POSIX Programmer's Manual LS(P)
2
6 ls - list directory contents
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9 ls [-CFRacdilqrtu1][-H | -L ][-fgmnopsx][file...]
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12 For each operand that names a file of a type other than directory or
13 symbolic link to a directory, ls shall write the name of the file as
14 well as any requested, associated information. For each operand that
15 names a file of type directory, ls shall write the names of files con‐
16 tained within the directory as well as any requested, associated infor‐
17 mation. If one of the -d, -F, or -l options are specified, and one of
18 the -H or -L options are not specified, for each operand that names a
19 file of type symbolic link to a directory, ls shall write the name of
20 the file as well as any requested, associated information. If none of
21 the -d, -F, or -l options are specified, or the -H or -L options are
22 specified, for each operand that names a file of type symbolic link to
23 a directory, ls shall write the names of files contained within the
24 directory as well as any requested, associated information.
25 If no operands are specified, ls shall write the contents of the cur‐
27 rent directory. If more than one operand is specified, ls shall write
28 non-directory operands first; it shall sort directory and non-directory
29 operands separately according to the collating sequence in the current
30 locale.
31 The ls utility shall detect infinite loops; that is, entering a previ‐
33 ously visited directory that is an ancestor of the last file encoun‐
34 tered. When it detects an infinite loop, ls shall write a diagnostic
35 message to standard error and shall either recover its position in the
36 hierarchy or terminate.
37
39 The ls utility shall conform to the Base Definitions volume of
40 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
41 The following options shall be supported:
43 -C Write multi-text-column output with entries sorted down the col‐
45 umns, according to the collating sequence. The number of text
46 columns and the column separator characters are unspecified, but
47 should be adapted to the nature of the output device.
48 -F Do not follow symbolic links named as operands unless the -H or
50 -L options are specified. Write a slash ( '/' ) immediately
51 after each pathname that is a directory, an asterisk ( '*' )
52 after each that is executable, a vertical bar ( '|' ) after each
53 that is a FIFO, and an at sign ( '@' ) after each that is a sym‐
54 bolic link. For other file types, other symbols may be written.
55 -H If a symbolic link referencing a file of type directory is spec‐
57 ified on the command line, ls shall evaluate the file informa‐
58 tion and file type to be those of the file referenced by the
59 link, and not the link itself; however, ls shall write the name
60 of the link itself and not the file referenced by the link.
61 -L Evaluate the file information and file type for all symbolic
63 links (whether named on the command line or encountered in a
64 file hierarchy) to be those of the file referenced by the link,
65 and not the link itself; however, ls shall write the name of the
66 link itself and not the file referenced by the link. When -L is
67 used with -l, write the contents of symbolic links in the long
68 format (see the STDOUT section).
69 -R Recursively list subdirectories encountered.
71 -a Write out all directory entries, including those whose names
73 begin with a period ( '.' ). Entries beginning with a period
74 shall not be written out unless explicitly referenced, the -a
75 option is supplied, or an implementation-defined condition shall
76 cause them to be written.
77 -c Use time of last modification of the file status information
79 (see <sys/stat.h> in the System Interfaces volume of
80 IEEE Std 1003.1-2001) instead of last modification of the file
81 itself for sorting ( -t) or writing ( -l).
82 -d Do not follow symbolic links named as operands unless the -H or
84 -L options are specified. Do not treat directories differently
85 than other types of files. The use of -d with -R produces
86 unspecified results.
87 -f Force each argument to be interpreted as a directory and list
89 the name found in each slot. This option shall turn off -l, -t,
90 -s, and -r, and shall turn on -a; the order is the order in
91 which entries appear in the directory.
92 -g The same as -l, except that the owner shall not be written.
94 -i For each file, write the file's file serial number (see stat()
96 in the System Interfaces volume of IEEE Std 1003.1-2001).
97 -l (The letter ell.) Do not follow symbolic links named as operands
99 unless the -H or -L options are specified. Write out in long
100 format (see the STDOUT section). When -l (ell) is specified, -1
101 (one) shall be assumed.
102 -m Stream output format; list files across the page, separated by
104 commas.
105 -n The same as -l, except that the owner's UID and GID numbers
107 shall be written, rather than the associated character strings.
108 -o The same as -l, except that the group shall not be written.
110 -p Write a slash ( '/' ) after each filename if that file is a
112 directory.
113 -q Force each instance of non-printable filename characters and
115 <tab>s to be written as the question-mark ( '?' ) character.
116 Implementations may provide this option by default if the output
117 is to a terminal device.
118 -r Reverse the order of the sort to get reverse collating sequence
120 or oldest first.
121 -s Indicate the total number of file system blocks consumed by each
123 file displayed. The block size is implementation-defined.
124 -t Sort with the primary key being time modified (most recently
126 modified first) and the secondary key being filename in the col‐
127 lating sequence.
128 -u Use time of last access (see <sys/stat.h>) instead of last modi‐
130 fication of the file for sorting ( -t) or writing ( -l).
131 -x The same as -C, except that the multi-text-column output is pro‐
133 duced with entries sorted across, rather than down, the columns.
134 -1 (The numeric digit one.) Force output to be one entry per line.
136 Specifying more than one of the options in the following mutually-
139 exclusive pairs shall not be considered an error: -C and -l (ell), -m
140 and -l (ell), -x and -l (ell), -C and -1 (one), -H and -L, -c and -u.
141 The last option specified in each pair shall determine the output for‐
142 mat.
143
145 The following operand shall be supported:
146 file A pathname of a file to be written. If the file specified is not
148 found, a diagnostic message shall be output on standard error.
149
152 Not used.
153
155 None.
156
158 The following environment variables shall affect the execution of ls:
159 COLUMNS
161 Determine the user's preferred column position width for writing
162 multiple text-column output. If this variable contains a string
163 representing a decimal integer, the ls utility shall calculate
164 how many pathname text columns to write (see -C) based on the
165 width provided. If COLUMNS is not set or invalid, an implementa‐
166 tion-defined number of column positions shall be assumed, based
167 on the implementation's knowledge of the output device. The col‐
168 umn width chosen to write the names of files in any given direc‐
169 tory shall be constant. Filenames shall not be truncated to fit
170 into the multiple text-column output.
171 LANG Provide a default value for the internationalization variables
173 that are unset or null. (See the Base Definitions volume of
174 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
175 ables for the precedence of internationalization variables used
176 to determine the values of locale categories.)
177 LC_ALL If set to a non-empty string value, override the values of all
179 the other internationalization variables.
180 LC_COLLATE
182 Determine the locale for character collation information in
184 determining the pathname collation sequence.
185 LC_CTYPE
187 Determine the locale for the interpretation of sequences of
188 bytes of text data as characters (for example, single-byte as
189 opposed to multi-byte characters in arguments) and which charac‐
190 ters are defined as printable (character class print).
191 LC_MESSAGES
193 Determine the locale that should be used to affect the format
194 and contents of diagnostic messages written to standard error.
195 LC_TIME
197 Determine the format and contents for date and time strings
198 written by ls.
199 NLSPATH
201 Determine the location of message catalogs for the processing of
202 LC_MESSAGES .
203 TZ Determine the timezone for date and time strings written by ls.
205 If TZ is unset or null, an unspecified default timezone shall be
206 used.
207
210 Default.
211
213 The default format shall be to list one entry per line to standard out‐
214 put; the exceptions are to terminals or when one of the -C, -m, or -x
215 options is specified. If the output is to a terminal, the format is
216 implementation-defined.
217 When -m is specified, the format used shall be:
219 "%s, %s, ...\n", <filename1>, <filename2>
222 where the largest number of filenames shall be written without exceed‐
224 ing the length of the line.
225 If the -i option is specified, the file's file serial number (see
227 <sys/stat.h>) shall be written in the following format before any other
228 output for the corresponding entry:
229 %u ", <file serial number>
232 If the -l option is specified without -L, the following information
234 shall be written:
235 "%s %u %s %s %u %s %s\n", <file mode>, <number of links>,
238 <owner name>, <group name>, <number of bytes in the file>,
239 <date and time>, <pathname>
240 If the file is a symbolic link, this information shall be about the
242 link itself and the <pathname> field shall be of the form:
243 "%s -> %s", <pathname of link>, <contents of link>
246 If both -l and -L are specified, the following information shall be
248 written:
249 "%s %u %s %s %u %s %s\n", <file mode>, <number of links>,
252 <owner name>, <group name>, <number of bytes in the file>,
253 <date and time>, <pathname of link>
254 where all fields except <pathname of link> shall be for the file
256 resolved from the symbolic link.
257 The -g, -n, and -o options use the same format as -l, but with omitted
259 items and their associated <blank>s. See the OPTIONS section.
260 In both the preceding -l forms, if <owner name> or <group name> cannot
262 be determined, or if -n is given, they shall be replaced with their
263 associated numeric values using the format %u .
264 The <date and time> field shall contain the appropriate date and time‐
266 stamp of when the file was last modified. In the POSIX locale, the
267 field shall be the equivalent of the output of the following date com‐
268 mand:
269 date "+%b %e %H:%M"
272 if the file has been modified in the last six months, or:
274 date "+%b %e %Y"
277 (where two <space>s are used between %e and %Y ) if the file has not
279 been modified in the last six months or if the modification date is in
280 the future, except that, in both cases, the final <newline> produced by
281 date shall not be included and the output shall be as if the date com‐
282 mand were executed at the time of the last modification date of the
283 file rather than the current time. When the LC_TIME locale category is
284 not set to the POSIX locale, a different format and order of presenta‐
285 tion of this field may be used.
286 If the file is a character special or block special file, the size of
288 the file may be replaced with implementation-defined information asso‐
289 ciated with the device in question.
290 If the pathname was specified as a file operand, it shall be written as
292 specified.
293 The file mode written under the -l, -g, -n, and -o options shall
295 consist of the following format:
296 "%c%s%s%s%c", <entry type>, <owner permissions>,
299 <group permissions>, <other permissions>,
300 <optional alternate access method flag>
301 The <optional alternate access method flag> shall be a single <space>
303 if there is no alternate or additional access control method associated
304 with the file; otherwise, a printable character shall be used.
305 The <entry type> character shall describe the type of file, as follows:
307 d Directory.
309 b Block special file.
311 c Character special file.
313 l (ell)
315 Symbolic link.
316 p FIFO.
318 - Regular file.
320 Implementations may add other characters to this list to represent
323 other implementation-defined file types.
324 The next three fields shall be three characters each:
326 <owner permissions>
328 Permissions for the file owner class (see the Base Definitions
330 volume of IEEE Std 1003.1-2001, Section 4.4, File Access Permis‐
331 sions).
332 <group permissions>
334 Permissions for the file group class.
336 <other permissions>
338 Permissions for the file other class.
340 Each field shall have three character positions:
343 1. If 'r' , the file is readable; if '-' , the file is not readable.
345 2. If 'w' , the file is writable; if '-' , the file is not writable.
347 3. The first of the following that applies:
349 S
351 If in <owner permissions>, the file is not executable and set-
352 user-ID mode is set. If in <group permissions>, the file is not
353 executable and set-group-ID mode is set.
354 s
356 If in <owner permissions>, the file is executable and set-user-
357 ID mode is set. If in <group permissions>, the file is exe‐
358 cutable and set-group-ID mode is set.
359 T
361 If in <other permissions> and the file is a directory, search
362 permission is not granted to others, and the restricted deletion
363 flag is set.
364 t
366 If in <other permissions> and the file is a directory, search
367 permission is granted to others, and the restricted deletion
368 flag is set.
369 x
371 The file is executable or the directory is searchable.
372 -
374 None of the attributes of 'S' , 's' , 'T' , 't' , or 'x'
375 applies.
376 Implementations may add other characters to this list for the third
379 character position. Such additions shall, however, be written in lower‐
380 case if the file is executable or searchable, and in uppercase if it is
381 not.
382 If any of the -l, -g, -n, -o, or -s options is specified, each list
384 of files within the directory shall be preceded by a status line indi‐
385 cating the number of file system blocks occupied by files in the direc‐
386 tory in 512-byte units, rounded up to the next integral number of
387 units, if necessary. In the POSIX locale, the format shall be:
388 "total %u\n", <number of units in the directory>
391 If more than one directory, or a combination of non-directory files and
393 directories are written, either as a result of specifying multiple op‐
394 erands, or the -R option, each list of files within a directory shall
395 be preceded by:
396 "\n%s:\n", <directory name>
399 If this string is the first thing to be written, the first <newline>
401 shall not be written. This output shall precede the number of units in
402 the directory.
403 If the -s option is given, each file shall be written with the number
405 of blocks used by the file. Along with -C, -1, -m, or -x, the number
406 and a <space> shall precede the filename; with -g, -l, -n, or -o, they
407 shall precede each line describing a file.
408
410 The standard error shall be used only for diagnostic messages.
411
413 None.
414
416 None.
417
419 The following exit values shall be returned:
420 0 Successful completion.
422 >0 An error occurred.
424
427 Default.
428 The following sections are informative.
430
432 Many implementations use the equal sign ( '=' ) to denote sockets bound
433 to the file system for the -F option. Similarly, many historical
434 implementations use the 's' character to denote sockets as the entry
435 type characters for the -l option.
436 It is difficult for an application to use every part of the file modes
438 field of ls -l in a portable manner. Certain file types and executable
439 bits are not guaranteed to be exactly as shown, as implementations may
440 have extensions. Applications can use this field to pass directly to a
441 user printout or prompt, but actions based on its contents should gen‐
442 erally be deferred, instead, to the test utility.
443 The output of ls (with the -l and related options) contains information
445 that logically could be used by utilities such as chmod and touch to
446 restore files to a known state. However, this information is presented
447 in a format that cannot be used directly by those utilities or be eas‐
448 ily translated into a format that can be used. A character has been
449 added to the end of the permissions string so that applications at
450 least have an indication that they may be working in an area they do
451 not understand instead of assuming that they can translate the permis‐
452 sions string into something that can be used. Future issues or related
453 documents may define one or more specific characters to be used based
454 on different standard additional or alternative access control mecha‐
455 nisms.
456 As with many of the utilities that deal with filenames, the output of
458 ls for multiple files or in one of the long listing formats must be
459 used carefully on systems where filenames can contain embedded white
460 space. Systems and system administrators should institute policies and
461 user training to limit the use of such filenames.
462 The number of disk blocks occupied by the file that it reports varies
464 depending on underlying file system type, block size units reported,
465 and the method of calculating the number of blocks. On some file system
466 types, the number is the actual number of blocks occupied by the file
467 (counting indirect blocks and ignoring holes in the file); on others it
468 is calculated based on the file size (usually making an allowance for
469 indirect blocks, but ignoring holes).
470
472 An example of a small directory tree being fully listed with ls -laRF a
473 in the POSIX locale:
474 total 11
477 drwxr-xr-x 3 hlj prog 64 Jul 4 12:07 ./
478 drwxrwxrwx 4 hlj prog 3264 Jul 4 12:09 ../
479 drwxr-xr-x 2 hlj prog 48 Jul 4 12:07 b/
480 -rwxr--r-- 1 hlj prog 572 Jul 4 12:07 foo*
481 a/b:
484 total 4
485 drwxr-xr-x 2 hlj prog 48 Jul 4 12:07 ./
486 drwxr-xr-x 3 hlj prog 64 Jul 4 12:07 ../
487 -rw-r--r-- 1 hlj prog 700 Jul 4 12:07 bar
488
490 Some historical implementations of the ls utility show all entries in a
491 directory except dot and dot-dot when a superuser invokes ls without
492 specifying the -a option. When "normal" users invoke ls without speci‐
493 fying -a, they should not see information about any files with names
494 beginning with a period unless they were named as file operands.
495 Implementations are expected to traverse arbitrary depths when process‐
497 ing the -R option. The only limitation on depth should be based on run‐
498 ning out of physical storage for keeping track of untraversed directo‐
499 ries.
500 The -1 (one) option was historically found in BSD and BSD-derived
502 implementations only. It is required in this volume of
503 IEEE Std 1003.1-2001 so that conforming applications might ensure that
504 output is one entry per line, even if the output is to a terminal.
505 Generally, this volume of IEEE Std 1003.1-2001 is silent about what
507 happens when options are given multiple times. In the cases of -C, -l,
508 and -1, however, it does specify the results of these overlapping
509 options. Since ls is one of the most aliased commands, it is important
510 that the implementation perform intuitively. For example, if the alias
511 were:
512 alias ls="ls -C"
515 and the user typed ls -1, single-text-column output should result, not
517 an error.
518 The BSD ls provides a -A option (like -a, but dot and dot-dot are not
520 written out). The small difference from -a did not seem important
521 enough to require both.
522 Implementations may make -q the default for terminals to prevent trojan
524 horse attacks on terminals with special escape sequences. This is not
525 required because:
526 * Some control characters may be useful on some terminals; for exam‐
528 ple, a system might write them as "\001" or "^A" .
529 * Special behavior for terminals is not relevant to applications
531 portability.
532 An early proposal specified that the optional alternate access method
534 flag had to be '+' if there was an alternate access method used on the
535 file or <space> if there was not. This was changed to be <space> if
536 there is not and a single printable character if there is. This was
537 done for three reasons:
538 1. There are historical implementations using characters other than
540 '+' .
541 2. There are implementations that vary this character used in that
543 position to distinguish between various alternate access methods in
544 use.
545 3. The standard developers did not want to preclude future specifica‐
547 tions that might need a way to specify more than one alternate
548 access method.
549 Nonetheless, implementations providing a single alternate access method
551 are encouraged to use '+' .
552 In an early proposal, the units used to specify the number of blocks
554 occupied by files in a directory in an ls -l listing were implementa‐
555 tion-defined. This was because BSD systems have historically used
556 1024-byte units and System V systems have historically used 512-byte
557 units. It was pointed out by BSD developers that their system has used
558 512-byte units in some places and 1024-byte units in other places.
559 (System V has consistently used 512.) Therefore, this volume of
560 IEEE Std 1003.1-2001 usually specifies 512. Future releases of BSD are
561 expected to consistently provide 512 bytes as a default with a way of
562 specifying 1024-byte units where appropriate.
563 The <date and time> field in the -l format is specified only for the
565 POSIX locale. As noted, the format can be different in other locales.
566 No mechanism for defining this is present in this volume of
567 IEEE Std 1003.1-2001, as the appropriate vehicle is a messaging system;
568 that is, the format should be specified as a "message".
569
571 The -s uses implementation-defined units and cannot be used portably;
572 it may be withdrawn in a future version.
573
575 chmod() , find , the System Interfaces volume of IEEE Std 1003.1-2001,
576 stat(), the Base Definitions volume of IEEE Std 1003.1-2001,
577 <sys/stat.h>
578
580 Portions of this text are reprinted and reproduced in electronic form
581 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
582 -- Portable Operating System Interface (POSIX), The Open Group Base
583 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
584 Electrical and Electronics Engineers, Inc and The Open Group. In the
585 event of any discrepancy between this version and the original IEEE and
586 The Open Group Standard, the original IEEE and The Open Group Standard
587 is the referee document. The original Standard can be obtained online
588 at http://www.opengroup.org/unix/online.html .
589IEEE/The Open Group 2003 LS(P)