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10.1 `ls‘: List directory contents
==================================
The `ls‘ program lists information about files (of any type, including
directories). Options and file arguments can be intermixed
arbitrarily, as usual.
For non-option command-line arguments that are directories, by
default `ls‘ lists the contents of directories, not recursively, and 不加任何选项的 ls 仅仅显示本级目录文件，不进行遍历
omitting files with names beginning with `.‘. For other non-option 且不显示隐藏文件，显示的内容仅仅是文件名
arguments, by default `ls‘ lists just the file name. If no non-option
argument is specified, `ls‘ operates on the current directory, acting
as if it had been invoked with a single argument of `.‘.
By default, the output is sorted alphabetically, according to the 显示结果是按字母排列，并且是按列显示
locale settings in effect.(1) If standard output is a terminal, the
output is in columns (sorted vertically) and control characters are
output as question marks; otherwise, the output is listed one per line
and control characters are output as-is.
Because `ls‘ is such a fundamental program, it has accumulated many
options over the years. They are described in the subsections below;
within each section, options are listed alphabetically (ignoring case).
The division of options into the subsections is not absolute, since some
options affect more than one aspect of `ls‘‘s operation.
Exit status:
0 success
1 minor problems (e.g., failure to access a file or directory not
specified as a command line argument. This happens when listing a
directory in which entries are actively being removed or renamed.)
2 serious trouble (e.g., memory exhausted, invalid option, failure
to access a file or directory specified as a command line argument
or a directory loop)
Also see *note Common options::.
* Menu:
* Which files are listed::
* What information is listed::
* Sorting the output::
* Details about version sort::
* General output formatting::
* Formatting file timestamps::
* Formatting the file names::
---------- Footnotes ----------
(1) If you use a non-POSIX locale (e.g., by setting `LC_ALL‘ to
`en_US‘), then `ls‘ may produce output that is sorted differently than
you‘re accustomed to. In that case, set the `LC_ALL‘ environment
variable to `C‘.
File: coreutils.info, Node: Which files are listed, Next: What information is listed, Up: ls invocation
10.1.1 Which files are listed
-----------------------------
These options determine which files `ls‘ lists information for. By
default, `ls‘ lists files and the contents of any directories on the
command line, except that in directories it ignores files whose names
start with `.‘.
（一）影藏文件的选择显示
`-a‘
`--all‘
In directories, do not ignore file names that start with `.‘.
`-A‘
`--almost-all‘
In directories, do not ignore all file names that start with `.‘;
ignore only `.‘ and `..‘. The `--all‘ (`-a‘) option overrides
this option.
相较于 -a 只忽略 这两个文件 “.” “..”
（二）文件类型的选择显示
`-d‘ 仅显示目录，对于链接文件，只显示链接，不显示链接内容
`--directory‘
List just the names of directories, as with other types of files,
rather than listing their contents. Do not follow symbolic links
listed on the command line unless the `--dereference-command-line‘
(`-H‘), `--dereference‘ (`-L‘), or
`--dereference-command-line-symlink-to-dir‘ options are specified.
`-R‘
`--recursive‘
List the contents of all directories recursively.
`-L‘ 显示链接的内容，且显示链接
`--dereference‘
When showing file information for a symbolic link, show information
for the file the link references rather than the link itself.
However, even with this option, `ls‘ still prints the name of the
link itself, not the name of the file that the link points to.
`-H‘ 显示链接的内容，但不显示链接本身
`--dereference-command-line‘
If a command line argument specifies a symbolic link, show
information for the file the link references rather than for the
link itself.
`--dereference-command-line-symlink-to-dir‘
Do not dereference symbolic links, with one exception: if a
command line argument specifies a symbolic link that refers to a
directory, show information for that directory rather than for the
link itself. This is the default behavior when no other
dereferencing-related option has been specified (`--classify‘
(`-F‘), `--directory‘ (`-d‘), (`-l‘), `--dereference‘ (`-L‘), or
`--dereference-command-line‘ (`-H‘)).
`-B‘
`--ignore-backups‘
In directories, ignore files that end with `~‘. This option is
equivalent to `--ignore=‘*~‘ --ignore=‘.*~‘‘.
`--group-directories-first‘
Group all the directories before the files and then sort the
directories and the files separately using the selected sort key
(see -sort option). That is, this option specifies a primary sort
key, and the -sort option specifies a secondary key. However, any
use of `--sort=none‘ (`-U‘) disables this option altogether.
`--hide=PATTERN‘
In directories, ignore files whose names match the shell pattern
PATTERN, unless the `--all‘ (`-a‘) or `--almost-all‘ (`-A‘) is
also given. This option acts like `--ignore=PATTERN‘ except that
it has no effect if `--all‘ (`-a‘) or `--almost-all‘ (`-A‘) is
also given.
This option can be useful in shell aliases. For example, if `lx‘
is an alias for `ls --hide=‘*~‘‘ and `ly‘ is an alias for `ls
--ignore=‘*~‘‘, then the command `lx -A‘ lists the file `README~‘
even though `ly -A‘ would not.
`-I PATTERN‘
`--ignore=PATTERN‘
In directories, ignore files whose names match the shell pattern
(not regular expression) PATTERN. As in the shell, an initial `.‘
in a file name does not match a wildcard at the start of PATTERN.
Sometimes it is useful to give this option several times. For
example,
$ ls --ignore=‘.??*‘ --ignore=‘.[^.]‘ --ignore=‘#*‘
The first option ignores names of length 3 or more that start with
`.‘, the second ignores all two-character names that start with `.‘
except `..‘, and the third ignores names that start with `#‘.
File: coreutils.info, Node: What information is listed, Next: Sorting the output, Prev: Which files are listed, Up: ls invocation
10.1.2 What information is listed
---------------------------------
These options affect the information that `ls‘ displays. By default,
only file names are shown.
`--author‘
List each file‘s author when producing long format directory
listings. In GNU/Hurd, file authors can differ from their owners,
but in other operating systems the two are the same.
`-D‘
`--dired‘
With the long listing (`-l‘) format, print an additional line after
the main output:
//DIRED// BEG1 END1 BEG2 END2 ...
The BEGN and ENDN are unsigned integers that record the byte
position of the beginning and end of each file name in the output.
This makes it easy for Emacs to find the names, even when they
contain unusual characters such as space or newline, without fancy
searching.
If directories are being listed recursively (`-R‘), output a
similar line with offsets for each subdirectory name:
//SUBDIRED// BEG1 END1 ...
Finally, output a line of the form:
//DIRED-OPTIONS// --quoting-style=WORD
where WORD is the quoting style (*note Formatting the file
names::).
Here is an actual example:
$ mkdir -p a/sub/deeper a/sub2
$ touch a/f1 a/f2
$ touch a/sub/deeper/file
$ ls -gloRF --dired a
a:
total 8
-rw-r--r-- 1 0 Jun 10 12:27 f1
-rw-r--r-- 1 0 Jun 10 12:27 f2
drwxr-xr-x 3 4096 Jun 10 12:27 sub/
drwxr-xr-x 2 4096 Jun 10 12:27 sub2/
a/sub:
total 4
drwxr-xr-x 2 4096 Jun 10 12:27 deeper/
a/sub/deeper:
total 0
-rw-r--r-- 1 0 Jun 10 12:27 file
a/sub2:
total 0
//DIRED// 48 50 84 86 120 123 158 162 217 223 282 286
//SUBDIRED// 2 3 167 172 228 240 290 296
//DIRED-OPTIONS// --quoting-style=literal
Note that the pairs of offsets on the `//DIRED//‘ line above
delimit these names: `f1‘, `f2‘, `sub‘, `sub2‘, `deeper‘, `file‘.
The offsets on the `//SUBDIRED//‘ line delimit the following
directory names: `a‘, `a/sub‘, `a/sub/deeper‘, `a/sub2‘.
Here is an example of how to extract the fifth entry name,
`deeper‘, corresponding to the pair of offsets, 222 and 228:
$ ls -gloRF --dired a > out
$ dd bs=1 skip=222 count=6 < out 2>/dev/null; echo
deeper
Note that although the listing above includes a trailing slash for
the `deeper‘ entry, the offsets select the name without the
trailing slash. However, if you invoke `ls‘ with `--dired‘ along
with an option like `--escape‘ (aka `-b‘) and operate on a file
whose name contains special characters, notice that the backslash
_is_ included:
$ touch ‘a b‘
$ ls -blog --dired ‘a b‘
-rw-r--r-- 1 0 Jun 10 12:28 a\ b
//DIRED// 30 34
//DIRED-OPTIONS// --quoting-style=escape
If you use a quoting style that adds quote marks (e.g.,
`--quoting-style=c‘), then the offsets include the quote marks.
So beware that the user may select the quoting style via the
environment variable `QUOTING_STYLE‘. Hence, applications using
`--dired‘ should either specify an explicit
`--quoting-style=literal‘ option (aka `-N‘ or `--literal‘) on the
command line, or else be prepared to parse the escaped names.
`--full-time‘
Produce long format directory listings, and list times in full.
It is equivalent to using `--format=long‘ with
`--time-style=full-iso‘ (*note Formatting file timestamps::).
`-g‘
Produce long format directory listings, but don‘t display owner
information.
`-G‘
`--no-group‘
Inhibit display of group information in a long format directory
listing. (This is the default in some non-GNU versions of `ls‘,
so we provide this option for compatibility.)
`-h‘
`--human-readable‘
Append a size letter to each size, such as `M‘ for mebibytes.
Powers of 1024 are used, not 1000; `M‘ stands for 1,048,576 bytes.
This option is equivalent to `--block-size=human-readable‘. Use
the `--si‘ option if you prefer powers of 1000.
`-i‘
`--inode‘
Print the inode number (also called the file serial number and
index number) of each file to the left of the file name. (This
number uniquely identifies each file within a particular file
system.)
`-l‘
`--format=long‘
`--format=verbose‘
In addition to the name of each file, print the file type, file
mode bits, number of hard links, owner name, group name, size, and
timestamp (*note Formatting file timestamps::), normally the
modification time. Print question marks for information that
cannot be determined.
Normally the size is printed as a byte count without punctuation,
but this can be overridden (*note Block size::). For example, `-h‘
prints an abbreviated, human-readable count, and
`--block-size="‘1"‘ prints a byte count with the thousands
separator of the current locale.
For each directory that is listed, preface the files with a line
`total BLOCKS‘, where BLOCKS is the total disk allocation for all
files in that directory. The block size currently defaults to 1024
bytes, but this can be overridden (*note Block size::). The
BLOCKS computed counts each hard link separately; this is arguably
a deficiency.
The file type is one of the following characters:
`-‘
regular file
`b‘
block special file
`c‘
character special file
`C‘
high performance ("contiguous data") file
`d‘
directory
`D‘
door (Solaris 2.5 and up)
`l‘
symbolic link
`M‘
off-line ("migrated") file (Cray DMF)
`n‘
network special file (HP-UX)
`p‘
FIFO (named pipe)
`P‘
port (Solaris 10 and up)
`s‘
socket
`?‘
some other file type
The file mode bits listed are similar to symbolic mode
specifications (*note Symbolic Modes::). But `ls‘ combines
multiple bits into the third character of each set of permissions
as follows:
`s‘
If the set-user-ID or set-group-ID bit and the corresponding
executable bit are both set.
`S‘
If the set-user-ID or set-group-ID bit is set but the
corresponding executable bit is not set.
`t‘
If the restricted deletion flag or sticky bit, and the
other-executable bit, are both set. The restricted deletion
flag is another name for the sticky bit. *Note Mode
Structure::.
`T‘
If the restricted deletion flag or sticky bit is set but the
other-executable bit is not set.
`x‘
If the executable bit is set and none of the above apply.
`-‘
Otherwise.
Following the file mode bits is a single character that specifies
whether an alternate access method such as an access control list
applies to the file. When the character following the file mode
bits is a space, there is no alternate access method. When it is
a printing character, then there is such a method.
GNU `ls‘ uses a `.‘ character to indicate a file with an SELinux
security context, but no other alternate access method.
A file with any other combination of alternate access methods is
marked with a `+‘ character.
`-n‘
`--numeric-uid-gid‘
Produce long format directory listings, but display numeric user
and group IDs instead of the owner and group names.
`-o‘
Produce long format directory listings, but don‘t display group
information. It is equivalent to using `--format=long‘ with
`--no-group‘ .
`-s‘ 从大到小排列，并且显示文件的 disk space
`--size‘
Print the disk allocation of each file to the left of the file
name. This is the amount of disk space used by the file, which is
usually a bit more than the file‘s size, but it can be less if the
file has holes.
Normally the disk allocation is printed in units of 1024 bytes,
but this can be overridden (*note Block size::).
For files that are NFS-mounted from an HP-UX system to a BSD
system, this option reports sizes that are half the correct
values. On HP-UX systems, it reports sizes that are twice the
correct values for files that are NFS-mounted from BSD systems.
This is due to a flaw in HP-UX; it also affects the HP-UX `ls‘
program.
`--si‘
Append an SI-style abbreviation to each size, such as `M‘ for
megabytes. Powers of 1000 are used, not 1024; `M‘ stands for
1,000,000 bytes. This option is equivalent to `--block-size=si‘.
Use the `-h‘ or `--human-readable‘ option if you prefer powers of
1024.
`-Z‘
`--context‘
Display the SELinux security context or `?‘ if none is found.
When used with the `-l‘ option, print the security context to the
left of the size column.
File: coreutils.info, Node: Sorting the output, Next: Details about version sort, Prev: What information is listed, Up: ls invocation
10.1.3 Sorting the output
-------------------------
These options change the order in which `ls‘ sorts the information it
outputs. By default, sorting is done by character code (e.g., ASCII
order).
（一）大小
`-S‘
`--sort=size‘
Sort by file size, largest first.
（二）时间
`-c‘ 创建时间
`--time=ctime‘
`--time=status‘
If the long listing format (e.g., `-l‘, `-o‘) is being used, print
the status change time (the `ctime‘ in the inode) instead of the
modification time. When explicitly sorting by time (`--sort=time‘
or `-t‘) or when not using a long listing format, sort according
to the status change time.
`-t‘ 内容修改时间
`--sort=time‘
Sort by modification time (the `mtime‘ in the inode), newest first.
`-u‘ 使用但没有修改的时间
`--time=atime‘
`--time=access‘
`--time=use‘
If the long listing format (e.g., `--format=long‘) is being used,
print the last access time (the `atime‘ in the inode). When
explicitly sorting by time (`--sort=time‘ or `-t‘) or when not
using a long listing format, sort according to the access time.
（三）进入目录的时间
`-f‘
Primarily, like `-U‘--do not sort; list the files in whatever
order they are stored in the directory. But also enable `-a‘ (list
all files) and disable `-l‘, `--color‘, and `-s‘ (if they were
specified before the `-f‘).
`-U‘
`--sort=none‘
Do not sort; list the files in whatever order they are stored in
the directory. (Do not do any of the other unrelated things that
`-f‘ does.) This is especially useful when listing very large
directories, since not doing any sorting can be noticeably faster.
（四）其他
`-f‘
Primarily, like `-U‘--do not sort; list the files in whatever
order they are stored in the directory. But also enable `-a‘ (list
all files) and disable `-l‘, `--color‘, and `-s‘ (if they were
specified before the `-f‘).
`-r‘ 将结果倒序显示
`--reverse‘
Reverse whatever the sorting method is--e.g., list files in reverse
alphabetical order, youngest first, smallest first, or whatever.
`-v‘
`--sort=version‘
Sort by version name and number, lowest first. It behaves like a
default sort, except that each sequence of decimal digits is
treated numerically as an index/version number. (*Note Details
about version sort::.)
`-X‘
`--sort=extension‘
Sort directory contents alphabetically by file extension
(characters after the last `.‘); files with no extension are
sorted first.
File: coreutils.info, Node: Details about version sort, Next: General output formatting, Prev: Sorting the output, Up: ls invocation
10.1.4 Details about version sort
---------------------------------
Version sorting handles the fact that file names frequently include
indices or version numbers. Standard sorting usually does not produce
the order that one expects because comparisons are made on a
character-by-character basis. Version sorting is especially useful
when browsing directories that contain many files with indices/version
numbers in their names:
$ ls -1 $ ls -1v
abc.zml-1.gz abc.zml-1.gz
abc.zml-12.gz abc.zml-2.gz
abc.zml-2.gz abc.zml-12.gz
Version-sorted strings are compared such that if VER1 and VER2 are
version numbers and PREFIX and SUFFIX (SUFFIX matching the regular
expression `(\.[A-Za-z~][A-Za-z0-9~]*)*‘) are strings then VER1 < VER2
implies that the name composed of "PREFIX VER1 SUFFIX" sorts before
"PREFIX VER2 SUFFIX".
Note also that leading zeros of numeric parts are ignored:
$ ls -1 $ ls -1v
abc-1.007.tgz abc-1.01a.tgz
abc-1.012b.tgz abc-1.007.tgz
abc-1.01a.tgz abc-1.012b.tgz
This functionality is implemented using gnulib‘s `filevercmp‘
function, which has some caveats worth noting.
* `LC_COLLATE‘ is ignored, which means `ls -v‘ and `sort -V‘ will
sort non-numeric prefixes as if the `LC_COLLATE‘ locale category
was set to `C‘.
* Some suffixes will not be matched by the regular expression
mentioned above. Consequently these examples may not sort as you
expect:
abc-1.2.3.4.7z
abc-1.2.3.7z
abc-1.2.3.4.x86_64.rpm
abc-1.2.3.x86_64.rpm
File: coreutils.info, Node: General output formatting, Next: Formatting file timestamps, Prev: Details about version sort, Up: ls invocation
10.1.5 General output formatting
--------------------------------
These options affect the appearance of the overall output.
`-1‘
`--format=single-column‘
List one file per line. This is the default for `ls‘ when standard
output is not a terminal.
`-C‘
`--format=vertical‘
List files in columns, sorted vertically. This is the default for
`ls‘ if standard output is a terminal. It is always the default
for the `dir‘ program. GNU `ls‘ uses variable width columns to
display as many files as possible in the fewest lines.
`--color [=WHEN]‘
Specify whether to use color for distinguishing file types. WHEN
may be omitted, or one of:
* none - Do not use color at all. This is the default.
* auto - Only use color if standard output is a terminal.
* always - Always use color.
Specifying `--color‘ and no WHEN is equivalent to `--color=always‘.
Piping a colorized listing through a pager like `more‘ or `less‘
usually produces unreadable results. However, using `more -f‘
does seem to work.
Note that using the `--color‘ option may incur a noticeable
performance penalty when run in a directory with very many entries,
because the default settings require that `ls‘ `stat‘ every single
file it lists. However, if you would like most of the file-type
coloring but can live without the other coloring options (e.g.,
executable, orphan, sticky, other-writable, capability), use
`dircolors‘ to set the `LS_COLORS‘ environment variable like this,
eval $(dircolors -p | perl -pe \
‘s/^((CAP|S[ET]|O[TR]|M|E)\w+).*/$1 00/‘ | dircolors -)
and on a `dirent.d_type‘-capable file system, `ls‘ will perform
only one `stat‘ call per command line argument.
`-F‘
`--classify‘
`--indicator-style=classify‘
Append a character to each file name indicating the file type.
Also, for regular files that are executable, append `*‘. The file
type indicators are `/‘ for directories, `@‘ for symbolic links,
`|‘ for FIFOs, `=‘ for sockets, `>‘ for doors, and nothing for
regular files. Do not follow symbolic links listed on the command
line unless the `--dereference-command-line‘ (`-H‘),
`--dereference‘ (`-L‘), or
`--dereference-command-line-symlink-to-dir‘ options are specified.
`--file-type‘
`--indicator-style=file-type‘
Append a character to each file name indicating the file type.
This is like `-F‘, except that executables are not marked.
`--indicator-style=WORD‘
Append a character indicator with style WORD to entry names, as
follows:
`none‘
Do not append any character indicator; this is the default.
`slash‘
Append `/‘ for directories. This is the same as the `-p‘
option.
`file-type‘
Append `/‘ for directories, `@‘ for symbolic links, `|‘ for
FIFOs, `=‘ for sockets, and nothing for regular files. This
is the same as the `--file-type‘ option.
`classify‘
Append `*‘ for executable regular files, otherwise behave as
for `file-type‘. This is the same as the `-F‘ or
`--classify‘ option.
`-k‘
`--kibibytes‘
Set the default block size to its normal value of 1024 bytes,
overriding any contrary specification in environment variables
(*note Block size::). This option is in turn overridden by the
`--block-size‘, `-h‘ or `--human-readable‘, and `--si‘ options.
The `-k‘ or `--kibibytes‘ option affects the per-directory block
count written by the `-l‘ and similar options, and the size
written by the `-s‘ or `--size‘ option. It does not affect the
file size written by `-l‘.
`-m‘
`--format=commas‘
List files horizontally, with as many as will fit on each line,
separated by `, ‘ (a comma and a space).
`-p‘
`--indicator-style=slash‘
Append a `/‘ to directory names.
`-x‘
`--format=across‘
`--format=horizontal‘
List the files in columns, sorted horizontally.
`-T COLS‘
`--tabsize=COLS‘
Assume that each tab stop is COLS columns wide. The default is 8.
`ls‘ uses tabs where possible in the output, for efficiency. If
COLS is zero, do not use tabs at all.
Some terminal emulators (at least Apple Terminal 1.5 (133) from
Mac OS X 10.4.8) do not properly align columns to the right of a
TAB following a non-ASCII byte. If you use such a terminal
emulator, use the `-T0‘ option or put `TABSIZE=0‘ in your
environment to tell `ls‘ to align using spaces, not tabs.
`-w‘
`--width=COLS‘
Assume the screen is COLS columns wide. The default is taken from
the terminal settings if possible; otherwise the environment
variable `COLUMNS‘ is used if it is set; otherwise the default is
80.
File: coreutils.info, Node: Formatting file timestamps, Next: Formatting the file names, Prev: General output formatting, Up: ls invocation
10.1.6 Formatting file timestamps
---------------------------------
By default, file timestamps are listed in abbreviated form, using a
date like `Mar 30 2002‘ for non-recent timestamps, and a
date-without-year and time like `Mar 30 23:45‘ for recent timestamps.
This format can change depending on the current locale as detailed
below.
A timestamp is considered to be "recent" if it is less than six
months old, and is not dated in the future. If a timestamp dated today
is not listed in recent form, the timestamp is in the future, which
means you probably have clock skew problems which may break programs
like `make‘ that rely on file timestamps.
Time stamps are listed according to the time zone rules specified by
the `TZ‘ environment variable, or by the system default rules if `TZ‘
is not set. *Note Specifying the Time Zone with `TZ‘: (libc)TZ
Variable.
The following option changes how file timestamps are printed.
`--time-style=STYLE‘
List timestamps in style STYLE. The STYLE should be one of the
following:
`+FORMAT‘
List timestamps using FORMAT, where FORMAT is interpreted
like the format argument of `date‘ (*note date invocation::).
For example, `--time-style="+%Y-%m-%d %H:%M:%S"‘ causes `ls‘
to list timestamps like `2002-03-30 23:45:56‘. As with
`date‘, FORMAT‘s interpretation is affected by the `LC_TIME‘
locale category.
If FORMAT contains two format strings separated by a newline,
the former is used for non-recent files and the latter for
recent files; if you want output columns to line up, you may
need to insert spaces in one of the two formats.
`full-iso‘
List timestamps in full using ISO 8601 date, time, and time
zone format with nanosecond precision, e.g., `2002-03-30
23:45:56.477817180 -0700‘. This style is equivalent to
`+%Y-%m-%d %H:%M:%S.%N %z‘.
This is useful because the time output includes all the
information that is available from the operating system. For
example, this can help explain `make‘‘s behavior, since GNU
`make‘ uses the full timestamp to determine whether a file is
out of date.
`long-iso‘
List ISO 8601 date and time in minutes, e.g., `2002-03-30
23:45‘. These timestamps are shorter than `full-iso‘
timestamps, and are usually good enough for everyday work.
This style is equivalent to `+%Y-%m-%d %H:%M‘.
`iso‘
List ISO 8601 dates for non-recent timestamps (e.g.,
`2002-03-30 ‘), and ISO 8601 month, day, hour, and minute for
recent timestamps (e.g., `03-30 23:45‘). These timestamps
are uglier than `long-iso‘ timestamps, but they carry nearly
the same information in a smaller space and their brevity
helps `ls‘ output fit within traditional 80-column output
lines. The following two `ls‘ invocations are equivalent:
newline=‘
‘
ls -l --time-style="+%Y-%m-%d $newline%m-%d %H:%M"
ls -l --time-style="iso"
`locale‘
List timestamps in a locale-dependent form. For example, a
Finnish locale might list non-recent timestamps like `maalis
30 2002‘ and recent timestamps like `maalis 30 23:45‘.
Locale-dependent timestamps typically consume more space than
`iso‘ timestamps and are harder for programs to parse because
locale conventions vary so widely, but they are easier for
many people to read.
The `LC_TIME‘ locale category specifies the timestamp format.
The default POSIX locale uses timestamps like `Mar 30 2002‘
and `Mar 30 23:45‘; in this locale, the following two `ls‘
invocations are equivalent:
newline=‘
‘
ls -l --time-style="+%b %e %Y$newline%b %e %H:%M"
ls -l --time-style="locale"
Other locales behave differently. For example, in a German
locale, `--time-style="locale"‘ might be equivalent to
`--time-style="+%e. %b %Y $newline%e. %b %H:%M"‘ and might
generate timestamps like `30. Ma"r 2002 ‘ and `30. Ma"r
23:45‘.
`posix-STYLE‘
List POSIX-locale timestamps if the `LC_TIME‘ locale category
is POSIX, STYLE timestamps otherwise. For example, the
`posix-long-iso‘ style lists timestamps like `Mar 30 2002‘
and `Mar 30 23:45‘ when in the POSIX locale, and like
`2002-03-30 23:45‘ otherwise.
You can specify the default value of the `--time-style‘ option with
the environment variable `TIME_STYLE‘; if `TIME_STYLE‘ is not set the
default style is `locale‘. GNU Emacs 21.3 and later use the `--dired‘
option and therefore can parse any date format, but if you are using
Emacs 21.1 or 21.2 and specify a non-POSIX locale you may need to set
`TIME_STYLE="posix-long-iso"‘.
To avoid certain denial-of-service attacks, timestamps that would be
longer than 1000 bytes may be treated as errors.
File: coreutils.info, Node: Formatting the file names, Prev: Formatting file timestamps, Up: ls invocation
10.1.7 Formatting the file names
--------------------------------
These options change how file names themselves are printed.
`-b‘
`--escape‘
`--quoting-style=escape‘
Quote nongraphic characters in file names using alphabetic and
octal backslash sequences like those used in C.
`-N‘
`--literal‘
`--quoting-style=literal‘
Do not quote file names. However, with `ls‘ nongraphic characters
are still printed as question marks if the output is a terminal
and you do not specify the `--show-control-chars‘ option.
`-q‘
`--hide-control-chars‘
Print question marks instead of nongraphic characters in file
names. This is the default if the output is a terminal and the
program is `ls‘.
`-Q‘
`--quote-name‘
`--quoting-style=c‘
Enclose file names in double quotes and quote nongraphic
characters as in C.
`--quoting-style=WORD‘
Use style WORD to quote file names and other strings that may
contain arbitrary characters. The WORD should be one of the
following:
`literal‘
Output strings as-is; this is the same as the `-N‘ or
`--literal‘ option.
`shell‘
Quote strings for the shell if they contain shell
metacharacters or would cause ambiguous output. The quoting
is suitable for POSIX-compatible shells like `bash‘, but it
does not always work for incompatible shells like `csh‘.
`shell-always‘
Quote strings for the shell, even if they would normally not
require quoting.
`c‘
Quote strings as for C character string literals, including
the surrounding double-quote characters; this is the same as
the `-Q‘ or `--quote-name‘ option.
`escape‘
Quote strings as for C character string literals, except omit
the surrounding double-quote characters; this is the same as
the `-b‘ or `--escape‘ option.
`clocale‘
Quote strings as for C character string literals, except use
surrounding quotation marks appropriate for the locale.
`locale‘
Quote strings as for C character string literals, except use
surrounding quotation marks appropriate for the locale, and
quote ‘like this‘ instead of "like this" in the default C
locale. This looks nicer on many displays.
You can specify the default value of the `--quoting-style‘ option
with the environment variable `QUOTING_STYLE‘. If that environment
variable is not set, the default value is `literal‘, but this
default may change to `shell‘ in a future version of this package.
`--show-control-chars‘
Print nongraphic characters as-is in file names. This is the
default unless the output is a terminal and the program is `ls‘.
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原文地址：http://www.cnblogs.com/IceSword-syy/p/3954341.html
