1.软件安装
sudo apt install
2.离线安装deb文件
dpkg -i package.deb #install
3.help 查看帮助 info
参考网站：https://lym.readthedocs.io
1.date
2.cal
3.whoami #whoami command will tell you which user account you are using in this system
4.id
5.pwd #pwd command will help you to find out the absolute path of the current directory
6.ls
7.mkdir #We can create new directoties using mkdir command
8.rm #rm command is used to remove a file, or directory.
9.cp #copy the file
cp ~/Pictures/1.jpg .
10.cp -r images /tem/
11.mv hello.txt nohello.txt
#12.tree #tree command prints the directory structure in a nice visual tree design way
13.cat
14.ls / > detial # Using > to redirect output to a file
source
Shell commands
===============
Linux shell or the terminal is the lifeline of the developers, and of any
power user. Things which can be done on the GUI (by clicking on different
buttons), can be done much efficiently on the terminal by using commands. One
can not remember all the commands, but with regular usage one can easily
remember the most useful ones.
The following guide will introduce you to some basic minimal commands
required to use your Linux computer efficiently.
Gnome Terminal
---------------
.. figure:: img/terminal1.png
:width: 600px
:align: center
The above is the screenshot of the Gnome terminal application. As you can see
the command prompt contains these following information::
[username@hostname directoryname]
In our case the username is *babai*, hostname is *kdas-laptop*, and directory
is mentioned as *~*. This *~* is a special character in our case. It means
the home directory of the user. In our case the home directory path is
*/home/babai/*.
What is a terminal and a shell?
--------------------------------
Read the articles on Wikipedia to learn about `computer teriminals
<https://en.wikipedia.org/wiki/Computer_terminal>`_, `terminal emulattors
<https://en.wikipedia.org/wiki/Terminal_emulator>`_ and `shell
<https://en.wikipedia.org/wiki/Shell_%28computing%29>`_.
date command
-------------
*date* command tells the current date time.
::
$Â date
Sun Jun 25 10:13:44 IST 2017
In case you want to know the current date/time in UTC, use the following command.
(I added this in 2018, so please do not get confused at the date).
::
$ date -u
Mon May 21 01:43:47 UTC 2018
cal command
------------
*cal* command is used to display calendar in your shell, by default it
will display the current month
::
$ cal
June 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
$ cal 07 2017
July 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
whoami command
---------------
*whoami* command will tell you which user account you are using in this system.
::
$ whoami
fedora
id command
-----------
*id* prints real user id, and various other details related to the account.
::
$ id
uid=1000(fedora) gid=1000(fedora) groups=1000(fedora),4(adm),10(wheel),190(systemd-journal) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
pwd command
------------
*pwd* command will help you to find out the absolute path of the current directory. Let us see an example below:
::
[babai@kdas-laptop ~]$ pwd
/home/babai
cd command
----------
The next command we will learn is *cd*. This command will help you to change your current directory. We will move
to */tmp* directory in our example.::
[babai@kdas-laptop ~]$ cd /tmp
[babai@kdas-laptop tmp]$ pwd
/tmp
[babai@kdas-laptop tmp]$ cd ~
[babai@kdas-laptop ~]$ pwd
/home/babai
Here you can see that first we moved to */tmp* directory, and then we moved
back to the home directory by using
*~* character.
. directory and .. directory
-----------------------------
*.* and *..* has special meaning in the Linux. *.* means the current
directory and *..* means the parent directory. We can use these in various
situations for daily activities.
::
$ cd ..
The above command moves to the parent directory.
ls command
----------
We use *ls* command to view the files and directories inside any given
directory. If you use *ls* command without any argument, then it will work on
the current directory. We will see few examples of the command below.::
[babai@kdas-laptop ~]$ ls
Desktop Documents Downloads Music Pictures Public Templates Videos
[babai@kdas-laptop ~]$ ls /tmp/
cpython systemd-private-759094c89c594c07a90156139ec4b969-colord.service-hwU1hR
hogsuspend systemd-private-759094c89c594c07a90156139ec4b969-rtkit-daemon.service-AwylGa
hsperfdata_babai tracker-extract-files.1000
plugtmp tracker-extract-files.1002
[babai@kdas-laptop ~]$ ls /
bin cpython etc lib lost+found mnt proc run srv sysroot usr
boot dev home lib64 media opt root sbin sys tmp var
In the last two commands we provided a path as the argument to the *ls*
command. */* is a special directory, which represents root directory in Linux
filesystem. You will know more in the next chapter.
mkdir command
-------------
We can create new directories using *mkdir* command. For our example we will
create a *code* directory in our home directory.::
[babai@kdas-laptop ~]$ mkdir code
[babai@kdas-laptop ~]$ ls
code Desktop Documents Downloads Music Pictures Public Templates Videos
We can also create directories in a recursive way using -p option.::
[babai@kdas-laptop ~]$ mkdir -p dir1/dir2/dir3
[babai@kdas-laptop ~]$ ls dir1/ dir1/dir2/
dir1/:
dir2
dir1/dir2/:
dir3
rm command
----------
*rm* command is used to remove a file, or directory. The *-rf* option is being
used to remove in a recursive way.
But, always double check before you use *rm -rf* command, if you by mistake
give this command in your home directory, or any other important directory,
it will not ask to confirm, but it will delete everything there.
*-f* stands for force, it will just delete everything. So, please be careful
*and read twice before pressing enter key*.
::
[babai@kdas-laptop ~]$ rm -rf dir1/dir2/dir3
[babai@kdas-laptop ~]$ ls dir1/ dir1/dir2/
dir1/:
dir2
dir1/dir2/:
Copying a file using cp command
-------------------------------
We use the *cp* command to copy a file in the Linux shell. To copy
recursively use the *cp* command with the *-r* flag.
We use the *cp file_to_copy new_location* format.
In the example below, we
are copying the *hello.txt* to *hello2.txt*.
::
$ cp hello.txt hello2.txt
$ ls -l
-rw-rw-r--. 1 fedora fedora 75 Jun 25 04:47 hello2.txt
-rw-rw-r--. 1 fedora fedora 75 Jun 25 04:33 hello.txt
In another example, I will copy the file *passwordauthno.png* from the
Pictures directory in my home directory to the current directory.
::
$ cp ~/Pictures/passwordauthno.png .
In the following example, I will be copying the *images* directory
(and everything inside it) from the *Downloads* directory under home
to the */tmp/* directory.
::
$ cp -r ~/Downloads/images /tmp/
Renaming or moving a file
--------------------------
The *mv* command is used to rename or move a file or directory. In the
following example, the file *hello.txt* is renamed to
*nothello.txt*
::
$ mv hello.txt nothello.txt
$ ls -l
-rw-rw-r--. 1 fedora fedora 75 Jun 25 04:33 nothello.txt
tree command
-------------
*tree* command prints the directory structure in a nice visual tree design way.::
[babai@kdas-laptop ~]$ tree
.
├── code
├── Desktop
├── dir1
│ └── dir2
├── Documents
├── Downloads
├── Music
├── Pictures
│ └── terminal1.png
├── Public
├── Templates
└── Videos
wc command
-----------
*wc* is an useful command which can help us to count newline, word and bytes
of a file.
::
$ cat hello.txt
HI that is a file.
This is the second line.
And we also have a third line.
$ wc -l hello.txt
3 hello.txt
$ wc -w hello.txt
17 hello.txt
The *-l* flag finds the number of line in a file, *-w* counts the number
of words in the file.
echo command
-------------
*echo* command echos any given string to the display.
::
$ echo "Hello"
Hello
Redirecting the command output
-------------------------------
In Linux shells, we can redirect the command output to a file, or as input to
another command. *|* is the most common way to do so. Using this we can now
count the number of directories in the root (*/*) directory very easily.
::
$ ls /
bin boot dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
$ ls / | wc -w
20
Using > to redirect output to a file
------------------------------------
We can use *>* to redirect the output of one command to a file, if the file
exists this will remove the old content and only keep the input. We can use
*>>* to append to a file, means it will keep all the old content, and
it will add the new input to the end of the file.
::
$ ls / > details.txt
$ cat details.txt
bin
boot
dev
etc
home
lib
lib64
lost+found
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var
$ ls /usr/ > details.txt
$ cat details.txt
bin
games
include
lib
lib64
libexec
local
sbin
share
src
tmp
$ ls -l /tmp/ >> details.txt
$ cat details.txt
bin
games
include
lib
lib64
libexec
local
sbin
share
src
tmp
total 776
-rwxrwxr-x. 1 fedora fedora 34 Jun 24 07:56 helol.py
-rw-------. 1 fedora fedora 784756 Jun 23 10:49 tmp3lDEho
Moving around in the command line
----------------------------------
There are key shortcuts available in Bash which will help you to move around faster.
The following table is a good starting point.
+-----------------+--------------------------------------+
| Key combination | Action |
+=================+======================================+
| Ctrl + A | Move to the beginning of the line |
+-----------------+--------------------------------------+
| Ctrl + E | Move to the end of the line |
+-----------------+--------------------------------------+
| Alt + B | Move to the previous word |
+-----------------+--------------------------------------+
| Alt + F | Move to the next word |
+-----------------+--------------------------------------+
| Ctrl + U | Erase to the beginning of the line |
+-----------------+--------------------------------------+
| Ctrl + K | Erase to the end of the line |
+-----------------+--------------------------------------+
| Ctrl + W | Erase the previous word |
+-----------------+--------------------------------------+
man pages
----------
*man* shows the system's manual pages. This is the command we use to
view the help document (manual page) for any command. The man pages are
organized based on *sections*, and if the same command is found in many
different sections, only the first one is shown.
The general syntax is *man section command*. Example **man 7 signal**.
You can know about different sections below. Press *q* to quit the program.
::
1 Executable programs or shell commands
2 System calls (functions provided by the kernel)
3 Library calls (functions within program libraries)
4 Special files (usually found in /dev)
5 File formats and conventions eg /etc/passwd
6 Games
7 Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
8 System administration commands (usually only for root)
9 Kernel routines [Non standard]