Linux Commands - Overview and Examples
The command line is one of the most powerful features of Linux. There exists a sea of Linux command line tools, allowing you to do almost everything you can think of doing on your Linux PC. However, this usually creates a problem: with so many commands available to use, you don't know where and how to start learning them, especially when you are beginner.
Author
Himanshu Arora：
印度理工學(xué)院失暴、伊利諾伊大學(xué)香檳分校滑黔；軟件開發(fā)工程師。
原文：https://www.howtoforge.com/linux-commands/
本文的特點是非常簡潔，將繁雜的Linux命令行篩選出100條左右，非常適合入門學(xué)習(xí)。
此外豪嗽，將領(lǐng)域知識以“條目+示例”的方式來整理，類似編字典一樣豌骏，在編輯的過程中可以促進學(xué)習(xí)者加深認識龟梦，也方便日后持續(xù)改進（增加注解、參考文獻窃躲、索引等）计贰，是一種不錯的學(xué)習(xí)方法。
最后蒂窒，整理這些命令行的時候躁倒，我體會到操作系統(tǒng)最重要的工作實際就是對文件的管理，創(chuàng)建刘绣、移動樱溉、查看、編輯纬凤、銷毀福贞、檢索，都是圍繞文件的操作停士，事實上也是實際工作中使用最頻繁的需求挖帘。對開發(fā)者來說完丽，以Linux命令行為模版，命名風(fēng)格拇舀、人機交互逻族、小而美的實現(xiàn)方式，促進自己在其它領(lǐng)域的應(yīng)用骄崩、提高大有裨益聘鳞。
Adduser/Addgroup
The adduser and addgroup commands lets you add a new user and group to a system, respectively. Here's an example for adduser:
$ sudo adduser testuser
Adding user `testuser' ...
Adding new group `testuser' (1003) ...
Adding new user `testuser' (1003) with group `testuser' ...
Creating home directory `/home/testuser' ...
Copying files from `/etc/skel' ...
Enter new UNIX password:
Arch
The arch command is used to print the machine's architecture. For example:
$ arch
i686
Not sure what 'i686' means? Head here.
Cal/Ncal
The cal and ncal commands display a calendar in the output.
$ cal
March 2017
Su Mo Tu We Th Fr Sa
1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31
$ ncal
March 2017
Su 5 12 19 26
Mo 6 13 20 27
Tu 7 14 21 28
We 1 8 15 22 29
Th 2 9 16 23 30
Fr 3 10 17 24 31
Sa 4 11 18 25
Cat
分類：文件管理脱惰；查看文件內(nèi)容
The cat command allows you to concatenate files, or data provided on standard input, and print it on the standard output. In layman terms, the command prints the information provided to it, whether through stdin or in the form a file.
$ cat test.txt
Hello...how are you?
Cd
分類：文件管理搏嗡；切換工作目錄
The cd command is used to change user's present working directory.
$ cd /home/himanshu/
Chgrp
分類：文件管理、權(quán)限管理拉一；切換文件所屬組
The chgrp command allows you to change the group ownership of a file. The command expects new group name as its first argument and the name of file (whose group is being changed) as second argument.
$ chgrp howtoforge test.txt
Chmod
分類：文件管理采盒、權(quán)限管理；切換文件執(zhí)行權(quán)限
The chmod command lets you change access permissions for a file. For example, if you have a binary file (say helloWorld), and you want to make it executable, you can run the following command:
chmod +x helloWorld
Chown
分類：文件管理蔚润、權(quán)限管理磅氨；切換文件所有者
The chown command allows you to change the ownership and group of a file. For example, to change the owner of a file test.txt to root, as well as set its group as root, execute the following command:
chown root:root test.txt
Cksum
分類：文件管理；查看文件屬性
The cksum command prints the CRC checksum and byte count for the input file.
$ cksum test.txt
3741370333 20 test.txt
Not sure what checksum is? Head here.
Clear
分類：人機交互抽碌；清屏
The clear command is used to clear the terminal screen.
$ clear
Cmp
分類：文件管理悍赢；文件比對 byte-by-byte
The cmp command is used to perform byte-by-byte comparison of two files.
$ cmp file1 file2
file1 file2 differ: byte 1, line 1
Comm
分類：文件管理；文件比對
The comm command is used to compare two sorted files line-by-line. For example, if 'file1' contains numbers 1-5 and 'file2' contains number 4-8, here's what the 'comm' command produces in this case:
$ comm file1 file2
支持選項：
-1：不顯示在第一個文件出現(xiàn)的內(nèi)容货徙；
-2：不顯示在第二個文件中出現(xiàn)的內(nèi)容左权；
-3：不顯示同時在兩個文件中都出現(xiàn)的內(nèi)容。
Cp
分類：文件管理痴颊；文件復(fù)制
The cp command is used for copying files and directories.
$ cp test.txt /home//himanshu/Desktop/
Csplit
分類：文件管理赏迟；待補充內(nèi)容
The csplit command lets you split a file into sections determined by context lines. For example, to split a file into two where the first part contains 'n-1' lines and the second contains the rest, use the following command:
$ csplit file1 [n]
The two parts are saved as files with names 'xx00' and 'xx01', respectively.
Date
分類：系統(tǒng)信息；查看系統(tǒng)時間
The date command can be used to print (or even set) the system date and time.
$ date
Tue Feb 28 17:14:57 IST 2017
Dd
分類：文件管理蠢棱；待補充內(nèi)容
The dd command copies a file, converting and formatting according to the operands. For example, the following command creates an image of /dev/sda partition.
dd if=/dev/sda of=/tmp/dev-sda-part.img
Df
分類：文件管理锌杀；查看文件系統(tǒng)利用率
The df command displays the file system disk space usage in output.
$ df /dev/sda1
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 74985616 48138832 23014620 68% /
Diff
分類：文件管理；文件比對 line-by-line
The diff command lets you compare two files line by line.
$ diff file1 file2
Diff3
分類：文件管理泻仙；文件比對,三個文件
The diff3 command, as the name suggests, allows you to compare three files line by line.
diff3 file1 file2 file3
Dir
分類：文件管理糕再；查看當前目錄文件列表
The dir command lists directory contents. For example:
$ dir
test1 test2 test.7z test.zip
Dirname
分類：文件管理；查看當前目錄
The dirname command strips last component from a file name/path. In layman's terms, you can think of it as a tool that, for example, removes file name from the file's absolute path.
$ dirname /home/himanshu/file1
/home/himanshu
Dmidecode
The dmidecode command prints a system's DMI (aka SMBIOS) table contents in a human-readable format.
$ sudo dmidecode
# dmidecode 2.12
SMBIOS 2.6 present.
50 structures occupying 2056 bytes.
Table at 0x000FCCA0.
Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
Vendor: American Megatrends Inc.
Version: 080015
Release Date: 08/22/2011
...
...
...
DMI (Desktop Management Interface, DMI)就是幫助收集電腦系統(tǒng)信息的管理系統(tǒng)突想，DMI信息的收集必須在嚴格遵照SMBIOS規(guī)范的前提下進行。 SMBIOS(System Management BIOS)是主板或系統(tǒng)制造者以標準格式顯示產(chǎn)品管理信息所需遵循的統(tǒng)一規(guī)范。SMBIOS和DMI是由行業(yè)指導(dǎo)機構(gòu)Desktop Management Task Force (DMTF)起草的開放性的技術(shù)標準猾担，其中DMI設(shè)計適用于任何的平臺和操作系統(tǒng)袭灯。
Du
分類：文件管理；查看指定目錄磁盤利用率
The du command displays disk usage of files present in a directory as well as its sub-directories.
$ du /home/himanshu/Desktop/
92 /home/himanshu/Desktop/Downloads/meld/meld/ui
88 /home/himanshu/Desktop/Downloads/meld/meld/vc
56 /home/himanshu/Desktop/Downloads/meld/meld/matchers
12 /home/himanshu/Desktop/Downloads/meld/meld/__pycache__
688 /home/himanshu/Desktop/Downloads/meld/meld
16 /home/himanshu/Desktop/Downloads/meld/bin
328 /home/himanshu/Desktop/Downloads/meld/data/ui
52 /home/himanshu/Desktop/Downloads/meld/data/icons/svg
Echo
The echo command displays whatever input text is given to it.
$ echo hello hi
hello hi
Ed
分類：文件管理绑嘹；編輯器
ed is a line-oriented text editor.
$ ed
單行純文本編輯器稽荧，它有命令模式（command mode）和輸入模式（input mode）兩種工作模式。
支持選項：
A：切換到輸入模式工腋，在文件的最后一行之后輸入新的內(nèi)容姨丈；
C：切換到輸入模式，用輸入的內(nèi)容替換掉最后一行的內(nèi)容夷蚊；
i：切換到輸入模式构挤，在當前行之前加入一個新的空行來輸入內(nèi)容髓介；
d：用于刪除最后一行文本內(nèi)容惕鼓；
n：用于顯示最后一行的行號和內(nèi)容；
w：<文件名>：一給定的文件名保存當前正在編輯的文件唐础；
q：退出ed編輯器箱歧。
Eject
分類：媒體管理；卸載
The eject command lets you eject removable media (typically, a CD ROM or floppy disk)
$ eject
Env
分類：系統(tǒng)信息一膨；查看用戶環(huán)境變量
The env command not only displays the current environment, but also lets you edit it.
$ env
Exit
分類：交互呀邢；退出
The exit command causes the shell to exit.
$ exit
Expand
分類：文件管理；編輯器豹绪；將TAB符替換為空格符
The expand command converts tabs present in the input file(s) into spaces, and writes the file contents to standard output.
$ expand file1
Expr
分類：計算器价淌；表達式
The expr command evaluates expressions. For example:
$ expr 1 + 2
3
Factor
分類：計算器；分解質(zhì)因數(shù)
The factor command prints the prime factors of the input number.
$ factor 135
135: 3 3 3 5
Fgrep
The fgrep command is equivalent to the grep command when executed with the -F command line option. The tool is also known as fixed or fast grep as it doesn't treat regular expression metacharacters as special, processing the information as simple string instead.
For example, if you want to search for dot (.) in a file, and don't want grep to interpret it as a wildcard character, use fgrep in the following way:
$ fgrep "." [file-name]
Find
分類：文件管理；搜索巷蚪；
The find command lets you search for files in a directory as well as its sub-directories.
$ find test*
test
test1
test2
test.7z
test.c
test.txt
More examples for the Linux Find command:
* 14 Practical Examples of Linux Find Command for Beginners
* Searching For Files And Folders With The find Command
* Finding Files On The Command Line
Fmt
分類：文件管理病毡；讀取文件內(nèi)容并格式化輸出（查看支持選項）
fmt is a simple optimal text formatter. It reformats each paragraph in the file passed to it, and writes the file contents to standard output.
$ fmt file1
Fold
The fold command wraps each input line to fit in specified width.
$ fold -w 10
Hi my name is himanshu Arora
Hi my name
is himans
hu Arora
Free
分類：系統(tǒng)信息屁柏；性能監(jiān)測啦膜；查看內(nèi)存利用情況。詳細介紹 >>>more>>>
The free command displays the amount of free and used memory in the system.
$ free
total used free shared buffers cached
Mem: 1800032 1355288 444744 79440 9068 216236
-/+ buffers/cache: 1129984 670048
Swap: 1832956 995076 837880
參考：基于Linux單機的負載評估
參考：Netflix性能分析模型：In 60 Seconds
Grep
分類：文件管理淌喻；搜索僧家；
The grep command searches for a specified pattern in a file (or files) and displays in output lines containing that pattern.
$ grep Hello test.txt
Hello...how are you?
More tutorials and examples for the Linux Grep command:
* How to use grep to search for strings in files on the shell
* How to perform pattern search in files using Grep
Groups
分類：文件管理；搜索裸删；
The groups command displays the name of groups a user is part of.
$ groups himanshu
himanshu : himanshu adm cdrom sudo dip plugdev lpadmin sambashare
Gzip
分類：文件管理八拱；壓縮
The gzip command compresses the input file, replacing the file itself with one having a .gz extension.
$ gzip file1
Gunzip
分類：文件管理；解壓縮
Files compressed with gzip command can be restored to their original form using the gunzip command.
$ gunzip file1.gz
Head
分類：文件管理；查看文件
The head command displays the first 10 lines of the file to standard output
$ head CHANGELOG.txt
BEEBEEP (Secure Lan Messanger)
BeeBEEP
2.0.4
- Some GUI improvements (new icons, file sharing tree load faster)
- Always Beep on new message arrived (option)
- Favorite users (right click on user and enable star button) is on top of the list
- improved group usability
- Offline users can be removed from list (right click on an offline user in list and then remove)
- Clear all files shared (option)
- Load minimized at startup (option)
Hostname
分類：系統(tǒng)信息乘粒；host name
The hostname command not only displays the system's host name, but lets them set it as well.
$ hostname
himanshu-desktop
Id
分類：系統(tǒng)信息豌注；用戶信息
The id command prints user and group information for the current user or specified username.
$ id himanshu
uid=1000(himanshu) gid=1000(himanshu) groups=1000(himanshu),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),124(sambashare)
Kill
分類：進程管理；
The kill command, as the name suggests, helps user kill a process by sending the TERM signal to it.
$ kill [process-id]
Killall
分類：進程管理灯萍；
The killall command lets you kill a process by name. Unlike kill - which requires ID of the process to be killed - killall just requires the name of the process.
$ killall nautilus
Last
分類：安全管理轧铁；查看最近登錄用戶
The last command shows listing of last logged in users.
$ last
himanshu pts/11 :0 Thu Mar 2 09:46 still logged in
himanshu pts/1 :0 Thu Mar 2 09:46 still logged in
himanshu :0 :0 Thu Mar 2 09:42 still logged in
reboot system boot 4.4.0-62-generic Thu Mar 2 09:41 - 10:36 (00:54)
himanshu pts/14 :0 Wed Mar 1 15:17 - 15:52 (00:35)
himanshu pts/13 :0 Wed Mar 1 14:40 - down (08:06)
Ldd
分類：軟件包管理；查看一個共享庫的依賴
The ldd command displays in output dependencies of a shared library.
$ ldd /lib/i386-linux-gnu/libcrypt-2.19.so
linux-gate.so.1 => (0xb77df000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb75da000)
/lib/ld-linux.so.2 (0x80088000)
Ln
分類：文件管理旦棉；鏈接
The ln command is used for creating link between files. For example, the following command would create a link named 'lnk' to a file with name 'test.txt':
$ ln test.txt lnk
Locate
分類：文件管理齿风；搜索
The locate command helps user find a file by name.
$ locate [file-name]
Logname
分類：登錄信息；
The logname command prints the user-name of the current user.
$ logname
himanshu
Ls
分類：文件管理绑洛；查看文件列表
The ls command lists contents of a directory in output.
$ ls progress
capture.png hlist.o progress progress.h sizes.c
hlist.c LICENSE progress.1 progress.o sizes.h
hlist.h Makefile progress.c README.md sizes.o
Lshw
分類：系統(tǒng)信息救斑；查看硬件信息
The lshw command extracts and displays detailed information on the hardware configuration of the machine.
$ sudo lshw
[sudo] password for himanshu:
himanshu-desktop
description: Desktop Computer
product: To Be Filled By O.E.M. (To Be Filled By O.E.M.)
vendor: To Be Filled By O.E.M.
version: To Be Filled By O.E.M.
serial: To Be Filled By O.E.M.
width: 32 bits
capabilities: smbios-2.6 dmi-2.6 smp-1.4 smp
...
...
..
Lscpu
分類：系統(tǒng)信息；查看硬件信息-CPU
The lscpu command displays in output system's CPU architecture information (such as number of CPUs, threads, cores, sockets, and more).
$ lscpu
Architecture: i686
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 1
On-line CPU(s) list: 0
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 1
Vendor ID: AuthenticAMD
CPU family: 16
Model: 6
Stepping: 3
CPU MHz: 2800.234
BogoMIPS: 5600.46
Virtualization: AMD-V
L1d cache: 64K
L1i cache: 64K
L2 cache: 1024K
Man
分類：幫助真屯；
man lets you access reference manual for commands, programs/utilities, as well as functions.
$ man ls
Md5sum
分類：計算器脸候；md5
The md5sum command lets you print or check MD5 (128-bit) checksums.
$ md5sum test.txt
ac34b1f34803a6691ff8b732bb97fbba test.txt
Mkdir
分類：文件管理；創(chuàng)建目錄
The mkdir command lets you create directories.
$ mkdir [dir-name]
Mkfifo
分類：進程管理
The mkfifo command is used to create named pipes.
$ mkfifo [pipe-name]
More
分類：交互
more is basically a filter for paging through text one screenful at a time.
$ cat [large-file] | more
Mv
分類：文件管理绑蔫；移動
The mv command lets you either move a file from one directory to another, or rename it.
$ mv test.txt /home/himanshu/Desktop/
Nice
分類：進程管理运沦；指定進程優(yōu)先級
The nice command lets you run a program with modified scheduling priority.
$ nice -n[niceness-value] [program]
$ nice -n15 vim
Nl
分類：文件管理；輸出行號
The nl command writes contents of a file to output, and prepends each line with line number.
$ nl file1
1 Hi
2 How are you
3 Bye
Nm
分類：文件管理
The nm command is used to display symbols from object files.
$ nm test
0804a020 B __bss_start
0804841d T compare
0804a020 b completed.6591
0804a018 D __data_start
0804a018 W data_start
08048360 t deregister_tm_clones
080483d0 t __do_global_dtors_aux
08049f0c t __do_global_dtors_aux_fini_array_entry
0804a01c D __dso_handle
08049f14 d _DYNAMIC
0804a020 D _edata
0804a024 B _end
080484e4 T _fini
080484f8 R _fp_hw
080483f0 t frame_dummy
...
...
...
Nproc
分類：進程管理
The nproc command displays the number of processing units available to the current process.
$ nproc
1
Od
分類：文件管理
The od command lets you dump files in octal as well as some other formats.
$ od /bin/ls
0000000 042577 043114 000401 000001 000000 000000 000000 000000
0000020 000002 000003 000001 000000 140101 004004 000064 000000
0000040 122104 000001 000000 000000 000064 000040 000011 000050
0000060 000034 000033 000006 000000 000064 000000 100064 004004
0000100 100064 004004 000440 000000 000440 000000 000005 000000
0000120 000004 000000 000003 000000 000524 000000 100524 004004
...
...
...
Passwd
分類：用戶權(quán)限管理
The passwd command is used for changing passwords for user accounts.
$ passwd himanshu
Changing password for himanshu.
(current) UNIX password:
Paste
分類：交互
The paste command lets you merge lines of files. For example, if 'file1' contains the following lines:
$ cat file1
Hi
My name is
Himanshu
Arora
I
Am
a
Linux researcher
and tutorial
writer
Then the following 'paste' command will join all the lines of the file:
$ paste -s file1
Hi My name is Himanshu Arora I Am a Linux researcher and tutorial writer
Pidof
分類：進程管理
The pidof command gives you the process ID of a running program/process.
$ pidof nautilus
2714
Ping
分類：網(wǎng)絡(luò)管理
The ping command is used to check whether or not a system is up and responding. It sends ICMP ECHO_REQUEST to network hosts.
$ ping howtoforge.com
PING howtoforge.com (104.24.0.68) 56(84) bytes of data.
64 bytes from 104.24.0.68: icmp_seq=1 ttl=58 time=47.3 ms
64 bytes from 104.24.0.68: icmp_seq=2 ttl=58 time=51.9 ms
64 bytes from 104.24.0.68: icmp_seq=3 ttl=58 time=57.4 ms
Ps
分類：進程管理
The ps command displays information (in the form of a snapshot) about the currently active processes.
$ ps
PID TTY TIME CMD
4537 pts/1 00:00:00 bash
20592 pts/1 00:00:00 ps
Pstree
分類：進程管理
The pstree command produces information about running processes in the form of a tree.
$ pstree
init???ModemManager???2*[{ModemManager}]
??NetworkManager???dhclient
? ??dnsmasq
? ??3*[{NetworkManager}]
??accounts-daemon???2*[{accounts-daemon}]
??acpid
??atop
Pwd
The pwd command displays the name of current/working directory.
$ pwd
/home/himanshu
Rm
分類：文件管理
The rm command lets you remove files and/or directories.
$ rm [file-name]
Rmdir
分類：文件管理
The rmdir command allows you delete empty directories.
$ rmdir [dir-name]
Scp
分類：文件管理
The scp command lets you securely copy files between systems on a network.
$ scp [name-and-path-of-file-to-transfer] [user]@[host]:[dest-path]
Sdiff
分類：文件管理配深；文本比對 side-by-side
The sdiff command lets you perform a side-by-side merge of differences between two files.
$ sdiff file1 file2
Sed
分類：文件管理;編程工具
sed is basically a stream editor that allows users to perform basic text transformations on an input stream (a file or input from a pipeline).
$ echo "Welcome to Howtoforge" | sed -e 's/Howtoforge/HowtoForge/g'
Welcome to HowtoForge
Seq
分類：計算器
The seq commands prints numbers from FIRST to LAST, in steps of INCREMENT. For example, if FIRST is 1, LAST is 10, and INCREMENT is 2, then here's the output this command produces:
$ seq 1 2 10
1
3
5
7
9
Sha1sum
分類：計算器
The sha1sum command is used to print or check SHA1 (160-bit) checksums.
$ sha1sum test.txt
955e48dfc9256866b3e5138fcea5ea0406105e68 test.txt
Shutdown
The shutdown command lets user shut the system in a safe way.
$ shutdown
Size
分類：文件管理
The size command lists the section sizes as well as the total size for an object or archive file.
$ size test
text data bss dec hex filename
1204 280 4 1488 5d0 test
Sleep
The sleep command lets user specify delay for a specified amount of time. You can use it to delay an operation like:
$ sleep 10; shutdown
Sort
分類：文件管理
The sort command lets you sort lines of text files. For example, if 'file2' contains the following names:
$ cat file2
zeus
kyan
sam
adam
Then running the sort command produces the following output:
$ sort file2
adam
kyan
sam
zeus
Split
分類：文件管理
The split command, as the name suggests, splits a file into fixed-size pieces. By default, files with name like xaa, xab, and xac are produced.
$ split [file-name]
Ssh
ssh is basically OpenSSH SSH client. It provides secure encrypted communication between two untrusted hosts over an insecure network.
$ ssh [user-name]@[remote-server]
Stat
分類：文件管理
The stat command displays status related to a file or a file-system.
$ stat test.txt
File: ‘test.txt’
Size: 20 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 284762 Links: 2
Access: (0664/-rw-rw-r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-03-03 12:41:27.791206947 +0530
Modify: 2017-02-28 16:05:15.952472926 +0530
Change: 2017-03-02 11:10:00.028548636 +0530
Birth: -
Strings
分類：文件管理
The strings command displays in output printable character sequences that are at least 4 characters long. For example, when a binary executable 'test' was passed as an argument to this command, following output was produced:
$ strings test
/lib/ld-linux.so.2
libc.so.6
_IO_stdin_used
puts
__libc_start_main
__gmon_start__
GLIBC_2.0
PTRh
QVhI
[^_]
EQUAL
;*2$"
GCC: (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
....
....
....
Su
分類：用戶權(quán)限管理
The su command lets you change user-identity. Mostly, this command is used to become root or superuser.
$ su [user-name]
Sudo
分類：用戶權(quán)限管理
The sudo command lets a permitted user run a command as another user (usually root or superuser).
$ sudo [command]
Sum
分類：文件管理
The sum command prints checksum and block counts for each input file.
$ sum readme.txt
45252 5
Tac
分類：文件管理
The tac command prints input files in reverse. Functionality-wise, it does the reverse of what the cat command does.
$ cat file2
zeus
kyan
sam
adam
$ tac file2
adam
sam
kyan
zeus
Tail
分類：文件管理
The tail command displays in output the last 10 lines of a file.
$ tail [file-name]
Talk
分類：網(wǎng)絡(luò)管理
The talk command lets users talk with each other.
$ talk [user-name]
Tar
分類：文件管理携添；壓縮&解壓縮
tar is an archiving utility that lets you create as well as extract archive files. For example, to create archive.tar from files 'foo' and 'bar', use the following command:
$ tar -cf archive.tar foo bar
More...
Tee
分類：文件管理
The tee command reads from standard input and write to standard output as well as files.
$ uname | tee file2
Linux
$ cat file2
Linux
Test
分類：計算器
The test command checks file types and compare values. For example, you can use it in the following way:
$ test 7 -gt 5 && echo "true"
true
Time
分類：性能監(jiān)測
The time command is used to summarize system resource usage of a program. For example:
$ time ping google.com
PING google.com (216.58.220.206) 56(84) bytes of data.
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=1 ttl=52 time=44.2 ms
^C
--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 44.288/44.288/44.288/0.000 ms
real 0m0.676s
user 0m0.000s
sys 0m0.000s
Top
分類：系統(tǒng)信息；性能監(jiān)測篓叶；性能概覽烈掠。詳細介紹 >>>more>>>
The top command gives a dynamic real-time view of a running system (in terms of its processes). For example:
$ top
參考：基于Linux單機的負載評估
參考：Netflix性能分析模型：In 60 Seconds
Touch
分類：文件管理
The touch command lets you change file timestamps (the access and modification times). When name of a non-existent file is passed as an argument, that file gets created.
$ touch [file-name]
Tr
分類：文件管理
The tr command can be used to translate/squeeze/delete characters. For example, here's how you can use it to convert lowercase characters to uppercase:
$ echo 'howtoforge' | tr "[:lower:]" "[:upper:]"
HOWTOFORGE
Tty
分類：資源管理
The tty command prints the filename of the terminal connected to standard input.
$ tty
/dev/pts/10
Uname
分類：用戶權(quán)限管理
The uname command prints certain system information.
$ uname -a
Linux himanshu-desktop 4.4.0-62-generic #83~14.04.1-Ubuntu SMP Wed Jan 18 18:10:26 UTC 2017 i686 athlon i686 GNU/Linux
Uniq
分類：文件管理；待補充信息
The Uniq command is used to report or omit repeated lines. For example, if 'file2' contains the following data:
$ cat file2
Welcome to HowtoForge
Welcome to HowtoForge
A Linux tutorial website
Thanks
Then you can use the uniq command to omit the repeated line.
$ uniq file2
Welcome to HowtoForge
A Linux tutorial website
Thanks
Unexpand
分類：文件管理缸托；待補充信息
The unexpand command converts spaces present in the input file(s) into tabs, and writes the file contents to standard output.
$ unexpand file1
Uptime
分類：系統(tǒng)信息左敌；性能監(jiān)測；查看負載嗦董。詳細介紹 >>>more>>>
The uptime command tells how long the system has been running.
$ uptime
15:59:59 up 6:20, 4 users, load average: 0.81, 0.92, 0.82
Users
分類：用戶權(quán)限管理母谎；待補充信息
The users command displays in output the usernames of users currently logged in to the current host.
$ users
himanshu himanshu himanshu himanshu
Vdir
分類：文件管理；待補充信息
The vdir command lists information about contents of a directory (current directory by default).
$ vdir
total 1088
-rw-rw-r-- 1 himanshu himanshu 4850 May 20 2015 test_backup.pdf
-rw-rw-r-- 1 himanshu himanshu 2082 May 28 2015 test-filled.pdf
-rw-rw-r-- 1 himanshu himanshu 7101 May 28 2015 test.pdf
Vim
分類：編輯器
vim is basically a text/programming editor. The name 'vim' stands for Vi IMproved as the editor is upwards compatible to the Vi editor.
$ vim [file-name]
W
分類：性能監(jiān)測
The w command displays information about the users currently on the machine, and their processes.
$ w
16:18:07 up 6:39, 4 users, load average: 0.07, 0.32, 0.53
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
himanshu :0 :0 09:39 ?xdm? 1:08m 0.25s init --user
himanshu pts/0 :0 09:41 6:36m 0.84s 7.84s gnome-terminal
himanshu pts/10 :0 14:51 0.00s 0.16s 0.00s w
himanshu pts/11 :0 15:41 35:19 0.05s 0.05s bash
Wall
分類：通訊京革；待補充信息
The wall command lets you write and send a message to other users that are currently logged in.
$ wall [your-message]
Watch
分類：性能監(jiān)測
The watch command can be used to monitor a program's output. It runs the program repeatedly, displaying its output and errors. For example:
$ watch date
Wc
分類：文件管理奇唤；待補充信息
The wc command prints newline, word, and byte counts for a file.
$ wc test.txt
0 3 20 test.txt
Whatis
分類：幫助
The whatis command displays single-line manual page descriptions.
$ whatis mkdir
mkdir (1) - make directories
mkdir (2) - create a directory
mkdir (1posix) - make directories
Which
分類：文件管理；以來
The which command basically lets you locate a command - the file and the path of the file that gets executed. For example:
$ which date
/bin/date
Who
分類：登錄信息
The who command shows who is logged on.
$ who
himanshu :0 2017-03-03 09:39 (:0)
himanshu pts/0 2017-03-03 09:41 (:0)
himanshu pts/10 2017-03-03 14:51 (:0)
himanshu pts/11 2017-03-03 15:41 (:0)
Whereis
分類：文件管理匹摇；以來
The whereis command shows in output locations of the binary, source, and manual page files for a command.
$ whereis ls
ls: /bin/ls /usr/share/man/man1/ls.1posix.gz /usr/share/man/man1/ls.1.gz
Whoami
分類：登錄信息
The whoami command prints effective userid of the current user.
$ whoami
himanshu
Xargs
分類：編程工具
The xargs command builds and executes command lines from standard input. In layman's terms, it reads items from stdin and executes a command passed to it as an argument. For example, here's how you can use xargs to find the word "Linux" in the files whose names are passed to it as input.
$ xargs grep "Linux"
file1
file2
file3
file1:Linux researcher
file2:A Linux tutorial website
file3:Linux is opensource
More...
Yes
分類：交互咬扇；確認
The Yes command outputs a string repeatedly until killed.
$ yes [string]
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