Linux trivial knowledge (tue-aug-21-01)

View historical operations

History 10 (List the last 10 actions)

!105 (Repeat 105th command)

!! (Repeat the previous command)

!last (executes the last command that starts with the end)

History | More (historical instructions itemized)

History-c (Clear all history commands)

Log

/var/log/message system startup information and error log, which is one of the most commonly used logs in red Hat Linux
/var/log/secure Security-related log information
/var/log/maillog message-related log information
/var/log/cron log information related to timed tasks
/var/log/spooler log information related to UUCP and news devices
/var/log/boot.log Daemon starts and stops related log messages

UNAME-A # View kernel/Os/cpu information

[Email protected] ~]# cat-n/etc/issue
1\s
2Kernel \ R on \m
3
[Email protected] ~]# Cat-b/etc/issue
1\s
2Kernel \ R on \m

The difference between Cat-n and Cat-b is:-B: List line numbers, do line numbers for non-blank lines only, blank lines do not line numbers, and N: Print travel numbers, along with blank lines, with line numbers, unlike the-B option;

To view the CentOS version:

[email protected] etc]# cat *-release
CentOS Linux release 7.5.1804 (Core)
Name= "CentOS Linux"
version= "7 (Core)"
Id= "CentOS"
Id_like= "Rhel Fedora"
Version_id= "7"
Pretty_name= "CentOS Linux 7 (Core)"
Ansi_color= "0;31"
Cpe_name= "Cpe:/o:centos:centos:7"
Home_url= "https://www.centos.org/"
Bug_report_url= "https://bugs.centos.org/"

centos_mantisbt_project= "CentOS-7"
centos_mantisbt_project_version= "7"
redhat_support_product= "CentOS"
redhat_support_product_version= "7"

CentOS Linux release 7.5.1804 (Core)
CentOS Linux release 7.5.1804 (Core)

Linux trivial knowledge (tue-aug-21-01)