As a Python developer , Just Python It's not enough .Linux It is also a language we often need to use .
In this article , I combed 11 Basic application commands , Also must learn . Let's share with you .
Ls The order is Linux The most common command in , yes list Abbreviation , By default ls The command is to list the current directory , If ls Specify a different directory , The list of files and folders in the specified directory will be displayed .
Common usage （ Common parameters ）:
（1） ls –l
In long format （ Only one file or directory information is displayed on each line ） List the details of files and directories , The output is as follows ：
[[email protected] single]$ ls -l
total 14091544
-rw-r-----. 1 oracle oinstall 5368717312 Apr 10 10:50 sysaux02.dbf
-rw-r-----. 1 oracle oinstall 9061015552 Apr 10 08:05 users01.dbf
（2） ls –a
List all files and directories in the directory , The output is as follows ：
[[email protected] single]$ ls -a
. .. sysaux02.dbf users01.dbf
（3） ls –s
List the total space occupied by the directory , And each file name and its size （ Unit is KB）, The output is as follows ：
[[email protected] single]$ ls -s
total 14091544
5242892 sysaux02.dbf 8848652 users01.dbf
（4） ls –lh
In long format （ Only one file or directory information is displayed on each line ）, And display the total size of files and directories in an intuitive form , The output is as follows ：
[[email protected] single]$ ls -lh
total 14G
-rw-r-----. 1 oracle oinstall 5.1G Apr 10 10:50 sysaux02.dbf
-rw-r-----. 1 oracle oinstall 8.5G Apr 10 08:05 users01.dbf
（5） ls –lrt
In long format （ Only one file or directory information is displayed on each line ）, And sort the files and directories according to the most time , The output is as follows ：
[[email protected] single]$ ls -lrt
total 14091544
-rw-r-----. 1 oracle oinstall 9061015552 Apr 10 08:05 users01.dbf
-rw-r-----. 1 oracle oinstall 5368717312 Apr 10 10:50 sysaux02.dbf
（6） ls –lrth
And “ls –lrt” comparison , Display the file size in a more intuitive way , The output is as follows ：
[[email protected]ngle single]$ ls -lrth
total 14G
-rw-r-----. 1 oracle oinstall 8.5G Apr 10 08:05 users01.dbf
-rw-r-----. 1 oracle oinstall 5.1G Apr 10 10:50 sysaux02.dbf
pwd The order is Print Working Directory Abbreviation , The basic function is to print the current working directory .
Common usage （ Common parameters ）：
（1） pwd
Displays the absolute path of the current directory , The output is as follows ：
[[email protected] oradata]$ pwd
/u01/oradata
（2） pwd -p
Displays the physical path of the current directory . Because some directories are link After the results of the , use -P Can be displayed link The source path of , The output is as follows ：
[email protected] oradata]$ cd /etc/init.d
[[email protected] init.d]$ pwd
/etc/init.d
[[email protected] init.d]$ pwd -P
/etc/rc.d/init.d
cd The order is linux One of the most common commands in , Used to switch directory paths
Common usage （ Common parameters ）：
（1） cd
Back to your own HOME Catalog , The output is as follows ：
[[email protected] init.d]$ pwd
/etc/init.d
[[email protected] init.d]$ cd
[[email protected] ~]$ pwd
/home/oracle
（2） cd –
Return to the directory before entering this directory , The output is as follows ：
[[email protected] ~]$ pwd
/home/oracle
[[email protected] ~]$ cd /u01/oradata/single
[[email protected] single]$ pwd
/u01/oradata/single
[[email protected] single]$ cd -
/home/oracle
[[email protected] ~]$ pwd
/home/oracle
（3） cd …
Go back to the previous Directory , The output is as follows ：
[[email protected] ~]$ pwd
/home/oracle
[[email protected] ~]$ cd ..
[[email protected] home]$ pwd
/home
（4） cd …/…
Returns the two directories above , The output is as follows ：
[[email protected] single]$ pwd
/u01/oradata/single
[[email protected] single]$ cd ../..
[[email protected] u01]$ pwd
/u01
（5） cd /u01
Switch to the specified directory path , The output is as follows ：
[[email protected] /]$ cd /u01
[[email protected] u01]$ pwd
/u01
grep yes global search regular expression(RE) Abbreviation , Is a powerful text search tool , It can search for text using regular expressions , And print out the matching lines .
（1） grep Command usage ：
grep [OPTIONS] PATTERN [FILE...]
grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]
（2） Common parameters （OPTIONS）
-a ： take binary Document to text Searching data by file
-c ： Calculate find ‘ Search string ’ The number of times
-i ： Ignore case differences , So case is the same
-n ： Output line number by the way
-v ： Reverse selection , That is to say, no ‘ Search string ’ Content line
-s： Do not display all lines that do not exist or have no matching text
–color： Add color to the key words found ( Value has ：never、always、auto Three ）
（3） Common regular expressions （PATTERN）
\： Ignore the original meaning of special characters in regular expressions .
^： Match the start line of the regular expression .
$: Match the end line of the regular expression .
<： From matching regular expression The line of form begins .
>： To the end of the line that matches the regular expression .
[ ]： Single character , Such as [A] namely A Meet the requirements .
[ - ]： Range , Such as [A-Z], namely A、B、C Until Z All meet the requirements .
.： All single characters .
*： Have a character , The length can be 0.
（4） Simple examples
Common usage or common parameters ：
Will include passwd The character file and its line are displayed ：
[[email protected] admin]$ grep -n passwd *
catexp7.sql:170: (name, userid, passwd, defrole, datats, tempts, profile#,
catzxs.sql:364: tmp := DBMS_XDB.CreateResource('/sys/xs/roles/dbms_passwd.xml',XSAUTHXSD);
csminst.sql:25:rem ywu 02/19/04 - fix bug 3434808, delete hard code passwd.
Will include 0-9 Take out the rows of numbers ：
[[email protected] admin]$ grep -n '[0-9]' xsu111.sql
2:Rem $Header: rdbms/admin/xsu111.sql /main/13 2010/06/06 21:49:30 snadhika Exp $
4:Rem xsu111.sql
6:Rem Copyright (c) 2007, 2010, Oracle and/or its affiliates.
cat It's a text file viewing and linking tool . Look at the contents of a file , use cat Relatively simple , Namely cat Followed by the file name .
Common usage （ Parameters ）：
（1）cat / file name
The simplest cat usage , Print out the whole contents of the whole document literally
（3） cat –b / file name
Print out the contents of the whole document , And number the non blank lines , Line number from 1 Start , The output is as follows ：
[[email protected] admin]$ cat -b xsu111.sql |more
1 Rem
2 Rem $Header: rdbms/admin/xsu111.sql /main/13 2010/06/06 21:49:30 snadhika Exp $
3 Rem
4 Rem xsu111.sql
5 Rem
……
similar cat command , However, it will be displayed page by page to facilitate users to read page by page , And the most basic command is to press the space bar （space） The next page shows , Press b The key will go back （back） One page shows , It also has the function of searching for strings （ And vi be similar ）
[[email protected] admin]$ more test.txt
Echo The command is to display the values of characters or variables on the screen .
Common usage ：
（1） Output string
The string to be output , Enclosed in double quotation marks , The output is as follows ：
[email protected] admin]$ echo "please wait 2 minute"
please wait 2 minute
（2） Output variable value
Output $ORACLE_HOME The value of the environment variable , The output is as follows ：
[[email protected] admin]$ echo $ORACLE_HOME
/dba/oracle/product/11.2.0/db_1
Display and set the name of the current host system , Only have ROOT Only users with permissions can set the hostname .
Common usage ：
（1） Display host name ：
[[email protected] admin]$ hostname
ol6-single
（2） Resolve the corresponding host name IP Address ：
Premise is /etc/hosts There is a corresponding host name in IP Address information , or DNS It can be parsed normally , The output is as follows ：
[[email protected] ~]# hostname -i
192.168.2.150
（3） Temporarily set the host name ：
Temporarily set the host name , After modification ,/etc/sysconfig/network In the document HOSTNAME The value remains unchanged , To permanently change the hostname , It needs to be revised /etc/sysconfig/network In file hostname Value , How to use it is as follows ：
[[email protected] ~]# hostname lijunjie
[[email protected] ~]# hostname
lijunjie
Touch The command is used to modify the time of accessing and changing the file to the current time or the specified time , Or create a new file that doesn't exist
Common usage ：
（1）touch file name
Used to create a new file , If the file name already exists , Then the modification time of the modified file is the current system time
[[email protected] admin]$ ls -l test.txt
-rw-r--r--. 1 oracle oinstall 31 Apr 11 05:18 test.txt
[[email protected] admin]$ date
Sat Apr 11 05:20:01 CST 2015
[[email protected] admin]$ touch test.txt
[[email protected] admin]$ ls -l test.txt
-rw-r--r--. 1 oracle oinstall 31 Apr 11 05:20 test.txt
（2）touch –r The source file name Destination filename
Put the time of the source file , Update to the target file , Make the time of two files the same
[[email protected] admin]$ ls -l
-rw-r--r--. 1 oracle oinstall 363 Sep 10 2014 listener.ora
-rw-r--r--. 1 oracle oinstall 31 Apr 11 05:20 test.txt
[[email protected] admin]$ touch -r listener.ora test.txt
[[email protected] admin]$ ls -lrt
-rw-r--r--. 1 oracle oinstall 31 Sep 10 2014 test.txt
-rw-r--r--. 1 oracle oinstall 363 Sep 10 2014 listener.ora
（4） touch –t yyyymmddhhmi.ss
Change the time of the document to the specified year 、 month 、 Japan 、 Hours 、 branch . second
[[email protected] admin]$ ls -l test.txt
-rw-r--r--. 1 oracle oinstall 31 Sep 10 2014 test.txt
[[email protected] admin]$ touch -t 201101012050.50 test.txt
[[email protected] admin]$ ls -l test.txt
-rw-r--r--. 1 oracle oinstall 31 Jan 1 2011 test.txt
Df The command is used to display details of file systems and directories .
Common usage ：
（1） df –a
List all file systems and mount points , The output is as follows ：
[[email protected] admin]$ df -a
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda3 10321208 3403240 6393680 35% /
proc 0 0 0 - /proc
sysfs 0 0 0 - /sys
devpts 0 0 0 - /dev/pts
tmpfs 507124 0 507124 0% /dev/shm
/dev/sda1 198337 50193 137904 27% /boot
/dev/sda2 39015880 27626000 9407928 75% /dba
none 0 0 0 - /proc/sys/fs/binfmt_misc
sunrpc 0 0 0 - /var/lib/nfs/rpc_pipefs
/dev/sdb1 51605436 15703408 33280624 33% /u01
（2）df -h
List the file systems and mount points that have been used and the size information that is easy to identify , The size information for easy identification is K、M、G Format , The output is as follows ;
[[email protected] admin]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 9.9G 3.3G 6.1G 35% /
tmpfs 496M 0 496M 0% /dev/shm
/dev/sda1 194M 50M 135M 27% /boot
/dev/sda2 38G 27G 9.0G 75% /dba
/dev/sdb1 50G 15G 32G 33% /u01
Exemplar Windows Notepad on , Used to edit the contents of a file or create a new file .
Master this 11 individual Linux Basic commands , Be a qualified Python developer ！
