Linux 基础知识整理（五）
Linux的常用命令 - ls命令
ls 命令是 Linux 系统中用来显示目标列表的命令，英文意思：list directory contents。
Linux命令 - ls—LZL在线工具
| 命令 | 描述 |
|---|---|
| ls -l | 长格式列出文件和目录 |
| ls -lh | 以人类可读的方式显示信息 |
| ls -a | 在列出的内容中包括隐藏文件 |
| ls -R | 递归列出文件 |
| ls -F | 在目录名后添加正斜杠 |
| ls *.ext | 列出具有特定扩展名的文件 |
| ls -lS | 根据文件大小排序 |
| ls -lt | 根据修改时间排序 |
| -r | 反转排序顺序（与 -S 或 -t 结合使用） |
利用 --help 参数查询 ls 的命令：
[root@icoolkj ~]# ls --help
Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--block-size=SIZE with -l, scale sizes by SIZE when printing them;
e.g., '--block-size=M'; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last
modification of file status information);
with -l: show ctime and sort by name;
otherwise: sort by ctime, newest first
-C list entries by columns
--color[=WHEN] colorize the output; WHEN can be 'always' (default
if omitted), 'auto', or 'never'; more info below
-d, --directory list directories themselves, not their contents
-D, --dired generate output designed for Emacs' dired mode
-f do not sort, enable -aU, disable -ls --color
-F, --classify append indicator (one of */=>@|) to entries
--file-type likewise, except do not append '*'
--format=WORD across -x, commas -m, horizontal -x, long -l,
single-column -1, verbose -l, vertical -C
--full-time like -l --time-style=full-iso
-g like -l, but do not list owner
--group-directories-first
group directories before files;
can be augmented with a --sort option, but any
use of --sort=none (-U) disables grouping
-G, --no-group in a long listing, don't print group names
-h, --human-readable with -l and -s, print sizes like 1K 234M 2G etc.
--si likewise, but use powers of 1000 not 1024
-H, --dereference-command-line
follow symbolic links listed on the command line
--dereference-command-line-symlink-to-dir
follow each command line symbolic link
that points to a directory
--hide=PATTERN do not list implied entries matching shell PATTERN
(overridden by -a or -A)
--hyperlink[=WHEN] hyperlink file names; WHEN can be 'always'
(default if omitted), 'auto', or 'never'
--indicator-style=WORD append indicator with style WORD to entry names:
none (default), slash (-p),
file-type (--file-type), classify (-F)
-i, --inode print the index number of each file
-I, --ignore=PATTERN do not list implied entries matching shell PATTERN
-k, --kibibytes default to 1024-byte blocks for disk usage;
used only with -s and per directory totals
-l use a long listing format
-L, --dereference when showing file information for a symbolic
link, show information for the file the link
references rather than for the link itself
-m fill width with a comma separated list of entries
-n, --numeric-uid-gid like -l, but list numeric user and group IDs
-N, --literal print entry names without quoting
-o like -l, but do not list group information
-p, --indicator-style=slash
append / indicator to directories
-q, --hide-control-chars print ? instead of nongraphic characters
--show-control-chars show nongraphic characters as-is (the default,
unless program is 'ls' and output is a terminal)
-Q, --quote-name enclose entry names in double quotes
--quoting-style=WORD use quoting style WORD for entry names:
literal, locale, shell, shell-always,
shell-escape, shell-escape-always, c, escape
(overrides QUOTING_STYLE environment variable)
-r, --reverse reverse order while sorting
-R, --recursive list subdirectories recursively
-s, --size print the allocated size of each file, in blocks
-S sort by file size, largest first
--sort=WORD sort by WORD instead of name: none (-U), size (-S),
time (-t), version (-v), extension (-X)
--time=WORD with -l, show time as WORD instead of default
modification time: atime or access or use (-u);
ctime or status (-c); also use specified time
as sort key if --sort=time (newest first)
--time-style=TIME_STYLE time/date format with -l; see TIME_STYLE below
-t sort by modification time, newest first
-T, --tabsize=COLS assume tab stops at each COLS instead of 8
-u with -lt: sort by, and show, access time;
with -l: show access time and sort by name;
otherwise: sort by access time, newest first
-U do not sort; list entries in directory order
-v natural sort of (version) numbers within text
-w, --width=COLS set output width to COLS. 0 means no limit
-x list entries by lines instead of by columns
-X sort alphabetically by entry extension
-Z, --context print any security context of each file
-1 list one file per line. Avoid '\n' with -q or -b
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
The TIME_STYLE argument can be full-iso, long-iso, iso, locale, or +FORMAT.
FORMAT is interpreted like in date(1). If FORMAT is FORMAT1FORMAT2,
then FORMAT1 applies to non-recent files and FORMAT2 to recent files.
TIME_STYLE prefixed with 'posix-' takes effect only outside the POSIX locale.
Also the TIME_STYLE environment variable sets the default style to use.
Using color to distinguish file types is disabled both by default and
with --color=never. With --color=auto, ls emits color codes only when
standard output is connected to a terminal. The LS_COLORS environment
variable can change the settings. Use the dircolors command to set it.
Exit status:
0 if OK,
1 if minor problems (e.g., cannot access subdirectory),
2 if serious trouble (e.g., cannot access command-line argument).
GNU coreutils online help:
or available locally via: info '(coreutils) ls invocation'
[root@icoolkj ~]#
-
列出隐藏文件
[root@icoolkj ~]# ls
dead.letter index.html index.html.1
[root@icoolkj ~]# ls -a
. .bash_history .bash_profile .cache .cshrc .groovy index.html.1 .java .m2 .npm .pki .rediscli_history .taos_history .viminfo
.. .bash_logout .bashrc .config dead.letter index.html .influxdbv2 .jenkins .mysql_history .pip .pydistutils.cfg .ssh .tcshrc
[root@icoolkj ~]# ls -A
.bash_history .bash_profile .cache .cshrc .groovy index.html.1 .java .m2 .npm .pki .rediscli_history .taos_history .viminfo
.bash_logout .bashrc .config dead.letter index.html .influxdbv2 .jenkins .mysql_history .pip .pydistutils.cfg .ssh .tcshrc
[root@icoolkj ~]# 以 . 开头的文件名就是所谓的隐藏文件（ls -A 与 ls -a 类似，但它不包括 . 和 .. 这两个目录）。
-
递归列出文件
[root@icoolkj tmp]# pwd
/usr/tmp
[root@icoolkj tmp]# ls -R
.:
aliyun-service.pid systemd-private-129ce6c23ffe48abb05f73f4d1a8f768-chronyd.service-CQUuFD
./systemd-private-129ce6c23ffe48abb05f73f4d1a8f768-chronyd.service-CQUuFD:
tmp
./systemd-private-129ce6c23ffe48abb05f73f4d1a8f768-chronyd.service-CQUuFD/tmp:
[root@icoolkj tmp]#
-
使用 ls 时对文件和目录做区分
[root@icoolkj tmp]# ls -F
aliyun-service.pid systemd-private-129ce6c23ffe48abb05f73f4d1a8f768-chronyd.service-CQUuFD/
[root@icoolkj tmp]#
不同的颜色就足以区分文件和目录。但是如果你基于某种原因需要给文件和目录添加符号标识，这就有一个办法。在 ls 命令中，使用 -F 选项，它会在每个目录名末尾添加一个正斜杠 /
-
基于大小对输出内容排序
[root@icoolkj lib]# ls -lhS
total 14M
-rwxr-xr-x 1 root root 8.7M 7月 24 19:05 libjemalloc.so.2
-rw-r--r-- 1 root root 4.8M 4月 11 2023 libyasm.a
-rw-r--r-- 1 root root 151K 4月 11 2023 libsrtp2.a
drwxr-xr-x 3 root root 4.0K 4月 11 2023 gcc
drwxr-xr-x 2 root root 4.0K 7月 24 19:05 pkgconfig
lrwxrwxrwx 1 root root 27 10月 15 2022 libfastcommon.so -> /usr/lib64/libfastcommon.so
lrwxrwxrwx 1 root root 27 10月 15 2022 libfdfsclient.so -> /usr/lib64/libfdfsclient.so
lrwxrwxrwx 1 root root 16 7月 24 19:05 libjemalloc.so -> libjemalloc.so.2
[root@icoolkj lib]#
如果颠倒这个顺序，使得最小的文件首先被列出，利用 -r 选项来实现反向排序（ls -lhSr）。
-
根据日期和时间排序文件
最新的文件最先被列出，可以使用 -t 选项
[root@icoolkj lib]# ls -lht
total 14M
drwxr-xr-x 2 root root 4.0K 7月 24 19:05 pkgconfig
lrwxrwxrwx 1 root root 16 7月 24 19:05 libjemalloc.so -> libjemalloc.so.2
-rwxr-xr-x 1 root root 8.7M 7月 24 19:05 libjemalloc.so.2
drwxr-xr-x 3 root root 4.0K 4月 11 2023 gcc
-rw-r--r-- 1 root root 151K 4月 11 2023 libsrtp2.a
-rw-r--r-- 1 root root 4.8M 4月 11 2023 libyasm.a
lrwxrwxrwx 1 root root 27 10月 15 2022 libfdfsclient.so -> /usr/lib64/libfdfsclient.so
lrwxrwxrwx 1 root root 27 10月 15 2022 libfastcommon.so -> /usr/lib64/libfastcommon.so
[root@icoolkj lib]#
当目录中存在大量文件，又希望最近被修改过的文件时，利用 -r 选项来实现反向排序（ls -lhSr）。
[root@icoolkj local]# ls -lrt
total 9488
drwxr-xr-x. 2 root root 4096 4月 11 2018 src
drwxr-xr-x. 2 root root 4096 4月 11 2018 games
drwxr-xr-x 11 root root 4096 10月 15 2022 nginx
drwxr-xr-x 9 root root 4096 10月 26 2022 mysql
drwxr-xr-x 3 root root 4096 11月 5 2022 maven
drwxr-xr-x. 2 root root 4096 4月 3 2023 sbin
drwxr-xr-x 4 root root 4096 4月 3 2023 clamav
drwxr-xr-x. 2 root root 4096 4月 3 2023 etc
drwxr-xr-x 4 root root 4096 4月 11 2023 doc
drwxr-xr-x 6 root root 4096 4月 11 2023 ffmpeg
drwxr-xr-x 5 root root 4096 4月 11 2023 cmake
lrwxrwxrwx 1 root root 7 4月 11 2023 ssl -> openssl
drwxr-xr-x 10 root root 4096 4月 11 2023 openssl
drwxr-xr-x 43 16446 ftp 4096 4月 11 2023 gcc-5.4.0
drwxr-xr-x. 3 root root 4096 4月 11 2023 libexec
drwxr-xr-x. 4 root root 4096 4月 11 2023 lib64
-rw-r--r-- 1 root root 71765 7月 15 18:25 dump.rdb
drwxr-xr-x 7 root root 4096 7月 24 19:05 taos
drwxr-xr-x. 7 root root 4096 7月 24 19:05 include
drwxr-xr-x. 4 root root 4096 7月 24 19:05 lib
-rw-r--r-- 1 root root 9549129 8月 2 14:10 appendonly.aof
drwxr-xr-x 8 root root 4096 9月 2 20:33 aegis
drwxr-xr-x. 16 root root 4096 11月 21 03:03 share
drwxr-xr-x. 3 root root 4096 12月 5 11:28 bin
[root@icoolkj local]#