Linux Command Rollup 1

Allow non-root users to use "sudo"

Root login system, execute "visudo", add a new rule according to the example (remember the password entered is the current user password, not the root password)
#不需要密码执行sudo命令
Hadoop all= (All) Nopasswd:all

Date

Time Stamp to date
Date-d ' 1970-01-01 UTC 1312438633.724 seconds ' + "%y-%m-%d%T"

#显示现在日期
Echo ' date-d now +%y%m%d '

#显示昨天日期
Echo ' date-d yesterday +%y%m%d '

#加减时间
Date +%y%m%d--date= "-1 day"
Date +%y%m%d%h--date= "-1 hour"

See what the site is server curl-s--head "http://www.baidu.com"

View Redhat version cat/etc/redhat-release #我这里显示 "CentOS release 5.5 (Final)" View Linux Max Open file count wrote Ulimit-a
# Focus on the screen display one line, you can see the maximum number of open files is 1024
Open files (-N) 1024

To set the number of open files:

Echo-ne "
* Soft Nofile 65536
* Hard Nofile 65536
">>/etc/security/limits.conf

After the launch of the terminal, in the implementation of ULIMIT-A, you can see that the changes have taken effect

Zip compressed file Zip {dist} {src}
zip-p {password} {dist} {src}

Only allow root Telnet cd/etc
Touch Nologin

Lock user, view machine 64-bit or 32-bit uname-m #会显示: "i686", "x86_64" cannot telnet (root only) passwd-l Hadoop

Unlock user (root only) passwd-u Hadoop

Lists the file paths of the RPM installer RPM-QL hadoop-0.20

View system already installed software Rpm-qa | grep Hadoop

View current server total CPU cores (number of cores) More/proc/cpuinfo | grep ' Processor ' | Wc-l

#查看每个CPU的核数
More/proc/cpuinfo | grep ' CPU cores '

#计算当前服务cpu数量
Total number of cores/cores per CPU

#查看CPU位数
Getconf Long_bit

To view the installation path for a program Whereis Java

View the path to the execution program which Java

Java code

1. # Modify DNS IP
2. Vi/etc/resolv.conf

Java code

1. #查看内存
2. Free

#查看CPU是否支持64操作系统, if the result is greater than 0, the description supports 64bit mode (long mode)
Cat/proc/cpuinfo | grep Flags | grep ' LM ' | Wc-l

#查看某行内容
Sed-n ' 100{p;q} ' filename

#查看用户所属组
grep "User name"/etc/group

#查看rpm包文件
Rpm2cpio hadoop.rpm | Cpio-idmv

#添加某个路径到运行时库, one line of path
Vi/etc/ld.so.conf
/usr/local/lib/
(or use an environment variable in such a way that does not require root access)
Export ld_library_path=/xxxxx: $LD _library_path

#centos下通过shell修改文件扩展名, rename <oldname> <newname> <*.files>
#将所有html扩展名改为htm扩展名
Rename. html. htm *.html
Specific reference: http://www.cyberciti.biz/tips/renaming-multiple-files-at-a-shell-prompt.html
#通过mv也可以实现修改扩展名这个功能
MV GoodYear. {htm,html}

Sort command #-U removes duplicate rows

#-R Descending (default to Ascending)

#-O output sorted after data, he with redirect ' > ' The biggest difference is the output data to the original file
Sort Seq.txt-o > Seq.txt

#-N Sort by numeric size

#-k Specifies sorting according to a column
Sort Num.txt-k2 # Sorted by second column (default delimiter is space, tab)

#-T specifies the column delimiter, only one character is supported
#-M Merge sort

The Linux command line parameter references the Run command:
./test.sh 111 222 333 444

Echo Run file name: $
#./test.sh

Echo First parameter: $
#111

echo number of parameters: $#
#4

Echo Last: $_
#444

echo all parameters, parameters are considered to be multiple strings: [email protected]
#111 222 333 444

echo all parameters, parameter is considered a string: $*
#111 222 333 444

echo Program PID: $$

Echo Exit code: $?

Less command tip1: Typing 50p, can enter 50% of the document location, support decimals, such as 95.5p

Script Change Password Write # method one
echo 123123 |passwd--stdin ABC
#方法二
#echo "Root:[email protected]# $QW 12qw" |chpasswd
#pwdadm-C Root

http://www.aixchina.net/club/thread-69699-1-1.html a line command to create a user and set a password useradd-p ' OpenSSL passwd <pwd> '-G <group_ Name> <username>

Create a user and disable Telnet useradd-s/sbin/nologin AK47

Query user crontab run record Cat/var/log/cron | grep <username>

Modify the Linux User directory usermod-d/home/hdfs-u hdfs disk speed test hdparm-t/dev/sda1

Quick Find file (according to file name) # Locate command is responsible for finding, updatedb command generating file index (daily)
Locate *qq*.txt

Chkconfig wrote Chkconfig--list | More # List all system services

Chkconfig <service_name> Off|on # Shut down, turn on system services

The first SSH login is not prompted to configure the SSH conf file stricthostkeychecking No


Top C # Display program full path
M # Sort by memory
P # Sorted by CPU

Top-p <pid> # View Process Top
#RES表示物理内存占用, the PS command is RSS representation of physical memory

bz2 File Decompression bunzip2 yy.bz2

View repetitions (shell-implemented group by + count) # Uniq must first sort,uniq the parameter-C to print the group repeat number
Cat xx. TXT | Sort | Uniq-c

The tar command uses TAR-ZCF my.tgz my # compression packaging
TAR-CF my.tgz My # do not compress packaging


TAR-ZXF my.tgz My # Unpacking package
TAR-XF my.tgz my # Uncompressed package

TAR-TF # View TAR package structure find #-o: or condition
# Find all the. htm and. html files at the end of the current directory
Find. \ (-name "*.htm"-o-name "*.html" \)

#-a:and Conditions

grep writes # finds lines in text that contain boy and girl
Cat My.txt | Grep-e ' Boy|girl '

# Find file name based on text content, "-h" for output file name
Find. -name ' *city* '-ls-exec zgrep ' null ' {}-h \;

# "or" lookup
Method One: grep ' pattern1\|pattern2 ' filename
Method Two: grep-e ' pattern1|pattern2 ' filename
Method Three: Egrep ' pattern1|pattern2 ' filename
Method Four: grep-e pattern1-e pattern2 filename

# "and" lookup
Method One: grep-e ' pattern1.*pattern2 ' filename
Method Two: grep-e ' pattern1 ' filename | Grep-e ' pattern2 '

Modify Hostname Method One: hostname <new hostname>
Method Two: Vi/etc/sysconfig/network

See the number of open files Lsof |wc-l
Lsof-p PID |wc-l

See which programs are using Disk Iotop

Create large file writes DD If=/dev/zero of=test bs=1m count=1000

#更大文件可以用下面这个, come on.
DD If=/dev/zero of=test bs=1m count=0 seek=100000

======================================

1. Check if the remote port is open for bash:

echo >/dev/tcp/8.8.8.8/53 && echo "open"

2. Turn the process into the background:

Ctrl + z

3. Transfer the process to the foreground:

fg

4. Generates a random hexadecimal number, where n is the number of characters:

openssl rand -hex n

5. Execute a command in a file in the current shell:

source /home/user/file.name

6. Intercept the first 5 characters:

${variable:0:5}

7.SSH Debug Mode:

ssh -vvv user@ip_address

8.SSH with PEM key:

ssh user@ip_address -i key.pem

9. Crawl the complete Site directory structure with wget and store it in a local directory:

"index.html*" http://hostname/ -P /home/user/dirs

10. Create more than one directory at a time:

mkdir -p /home/user/{test,test1,test2}

11. List the process tree that includes the child processes:

ps axwef

12. Create the War file:

jar -cvf name.war file

13. Test HDD Write Speed:

if=/dev/zero of=/tmp/output.img bs=8k count=256k; rm -rf /tmp/output.img

14. Test Drive Read Speed:

hdparm -Tt /dev/sda

15. Get the MD5 hash of the text:

"text" | md5sum

16. Check the XML format:

xmllint --noout file.xml

17. Extract the tar.gz into the new directory:

tar zxvf package.tar.gz -C new_dir

18. Get the HTTP header information using curl:

curl -I http://www.example.com

19. Modify the timestamp (YYMMDDHHMM) of the file or directory:

0712250000 file

20. Perform an FTP download with the wget command:

wget -m ftp://username:password@hostname

21. Generate a random password (the example is 16 characters in length):

LANG=c < /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c${1:-16};echo;

22. Quickly back up a file:

cp some_file_name{,.bkp}

23. Access the Windows shared directory:

"DOMAIN\user" //dc.domain.com/share/test/dir

24. The command in the execution history (this is line 100th):

!100

25. Unzip:

unzip package_name.zip -d dir_name

26. Enter multiple lines of text (CTRL + D exit):

cat > test.txt

27. Create an empty file or empty an existing file:

\> test.txt

28. Sync time with Ubuntu NTP server:

ntpdate ntp.ubuntu.com

29. Display all TCP4 listening ports with netstat:

‘{print $4}‘ | cut -f2 -d: | grep -o ‘[0-9]*‘

30.qcow2 image File Conversion:

qemu-img convert -f qcow2 -O raw precise-server-cloudimg-amd64-disk1.img \precise-server-cloudimg-amd64-disk1.raw

31. Run the file repeatedly, showing its output (by default, 2 seconds):

watch ps -ef

32. List of all users:

getent passwd

33.Mount root in Read/write mode:

mount -o remount,rw /

34. Mount a directory (this is a case where links cannot be used):

mount --bind /source /destination

35. Dynamically update DNS server:

86400 A $IPsendEOF

36. Recursive grep all directories:

"some_text" /path/to/dir

37. List the top 10 largest files:

‘{ if($7 > 1048576) print $7/1048576 "MB "$9 }‘ | sort -n -u | tail

38. Show remaining memory (MB):

‘/[0-9]/{ print $4" MB" }‘

39. Open vim and jump to the end of the file:

vim + some_file_name

40.Git clones the specified branch (master):

git clone git@github.com:name/app.git -b master

41.Git Switch to another branch (develop):

git checkout develop

42.Git Delete Branch (myfeature):

git branch -d myfeature

43.Git Delete Remote Branch

git push origin :branchName

44.Git Push the new branch to the remote server:

git push -u origin mynewfeature

45. Last Cat command in print history:

!cat:p

46. Last cat command in the Run history:

!cat

47. Find all the empty empty directories under/home/user:

1 -type d -empty

48. Get the contents of the 第50-60 line in the Test.txt file:

‘50,60p‘

49. Run the last command (if the last command is Mkdir/root/test, the following will run: sudo mkdir/root/test):

sudo !!

50. Create temporary RAM file System –ramdisk (create/tmpram directory first):

mount -t tmpfs tmpfs /tmpram -o size=512m

51.Grep whole words:

"name" test.txt

52. Append text to a file in case you need to elevate your privileges:

"some text" | sudo tee -a /path/file

53. List all kill signal parameters:

kill -l

54. Prohibit logging of the last session in bash history:

kill -9 $$

55. Scan the network for open ports:

8081 172.20.0.0/16

56. Set up git email:

git config --global user.email "[email protected]"

57.To sync with Master If you have unpublished commits:

git pull --rebase origin master

58. Move all files with "TXT" in the file name into the/home/user directory:

"*txt*" -exec mv -v {} /home/user \;

59. Display the file in rows and lines:

paste test.txt test1.txt

Progress bar in 60.shell:

pv data.log

61. Use Netcat to send data to Graphite server:

"hosts.sampleHost 10 `date +%s`" | nc 192.168.200.2 3000

62. Convert Tabs to spaces:

expand test.txt > test1.txt

63.Skip Bash History:

< space >cmd

64. Go to the previous working directory:

cd -

65. Split the large volume tar.gz file (each 100MB) and merge it back in:

100m /path/to/large/archive /path/to/output/filescat files* > archive

66. Use Curl to get the HTTP status code:

"%{http_code}\\n" www.example.com -o /dev/null

67. Set the root password to enhance MySQL security installation:

/usr/bin/mysql_secure_installation

68. When Ctrl + C is not good to make:

Ctrl + \

69. Get the file owner:

stat -c %U file.txt

70.block Device List:

lsblk -f

71. Locate the file with a space at the end of the file name:

find . -type f -exec egrep -l " +$" {} \;

72. Find the file with the tab indent in the filename

find . -type f -exec egrep -l $‘\t‘ {} \;

73. Print a horizontal line with "=": Select Copy to put in notes

‘%100s\n‘ | tr ‘ ‘ =

Related connections:

My Linux command notes

73 Daily Linux Shell command Summary, there is always one you need

Linux Command Rollup 1