Summary of Linux knowledge points and Linux knowledge points

Source: Internet
Author: User

Summary of Linux knowledge points and Linux knowledge points

 

1. crontab (1) crontab is executed every 10 seconds
* * * * * /bin/date >>/tmp/date.txt * * * * * sleep 10; /bin/date >>/tmp/date.txt 
(2) You can also use the following methods to express

string            meaning  
------           -------  
@reboot        Run once, at startup.  
@yearly         Run once a year,  " 0 0 1 1 * ".  
@annually      (same as  @yearly)  
@monthly       Run once a month,  " 0 0 1 * * ".  
@weekly        Run once a week,  " 0 0 * * 0 ".  
@daily           Run once a day,  " 0 0 * * * ".  
@midnight      (same as  @daily)  
@hourly         Run once an hour,  " 0 * * * * 

2. Kick the user offline
root@iZ94hgp4s2xZ:~# w  10:15:27 up 1 day, 19:20,  2 users,  load average: 0.00, 0.01, 0.05 USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT jediael  pts/0    218.107.55.252   09:15   31.00s  0.13s  0.13s -bash root     pts/1    218.107.55.252   10:15    1.00s  0.02s  0.00s w root@iZ94hgp4s2xZ:~# pkill -kill -t pts/0 
3. Several bin directories/bin: commands related to boot, including system repairs in single-user mode, such as cp mv bash dmsg grep chmod/sbin: Same as above, generally, root is allowed to use commands such as init iptables lvm/usr/bin: commands unrelated to startup: java tail gcc/usr/sbin: Same as above, generally, the root command useradd usermod/usr/local/bin: when the same software requires a different version but does not want to delete the original version, install the new software here/user/local/sbin: Same as above, general commands used by root 4. view the memory and cpu information in the proc file system cat/proc/cpuinfo cat/proc/meminfo 5. Some Common commands and options
cat /etc/passwd | cut -d ':' -f 1 apt-cache dumpavail | grep  'Package: mysql’ cat /etc/passwd | sort -t ':' -k 3 -n last | cut -d ' ' -f 1 | sort | uniq -c 
 
6. basic steps of disk partitioning (1) create a partition fdisk (2) format the partition mkfs (3) Check the disk and fsck (4) mount the disk
7. apt Common commands (1) install apt-get install scala (2) specify a certain version of apt-get install calla = 2.9.2 (3) delete a software apt-get remove scala (4) search for a software apt-cache search scala

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.