Character set modification, Linux time synchronization, tuning file descriptors

Character

UTF-8: Non-fixed length, 1-4 bytes, widely supported, most widely used

GBK: Fixed length, double byte, not international standard, less supported systems

[Email protected] ~]# cat/etc/sysconfig/i18n

Lang= "en_US. UTF-8 "

Sysfont= "Latarcyrheb-sun16"

Backup first:

[Email protected] ~]# cp/etc/sysconfig/i18n/etc/sysconfig/i18n.wuyike.20170411

Change configuration:

[Email protected] ~]# sed-i ' s#lang= "en_US. UTF-8 "#lang=" ZH_CN. UTF-8 "#g '/etc/sysconfig/i18n

[Email protected] ~]# cat/etc/sysconfig/i18n

Lang= "ZH_CN. UTF-8 "

Sysfont= "Latarcyrheb-sun16"

[Email protected] ~]# echo $LANG

en_US. UTF-8

[Email protected] ~]# source/etc/sysconfig/i18n

[Email protected] ~]# echo $LANG

Zh_cn. UTF-8

Then change the character set in the CRT: Session option----and character encoding-->utf-8.

Time Service:

[[Email protected] ~]# Date

Saturday, March 04, 2017 18:57:16 CST

Modification Time:

[[email protected] ~]# date-s "2017/04/11 20:38"

April 11, 2017 Tuesday 20:38:00 CST

[[Email protected] ~]# Date

April 11, 2017 Tuesday 20:38:05 CST

Save time:

[Email protected] ~]# Hwclock

April 11, 2017 Tuesday 20:38 23 sec -0.344922 seconds

Sync Internet time:

[Email protected] ~]#/usr/sbin/ntpdate time.nist.gov

APR 20:41:29 ntpdate[35435]: Step time Server 216.229.0.179 offset-604646.549696 sec

Set the Internet to sync every 5 minutes on Crond

[[email protected] ~]# echo "*/5 * * * */usr/sbin/ntpdate time.nist.gov" >/dev/null 2>&1 ">>/VAR/SPOOL/CR On/root

Or start the Linux automatic synchronization Internet program:

[[email protected] ~]#/etc/init.d/ntpd start

NTP service:

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To set the timeout control for the CRT:

[Email protected] ~]# export tmout=10

[[email protected] ~]# timed out waiting for input:auto-logout

[Email protected] ~]$

Permanently set timeout control

[Email protected] ~]# echo "Export tmout=10" >>/etc/profile

[Email protected] ~]# Source/etc/profile

View:

[Email protected] ~]# echo $TMOUT

1000

Historical records Control:

History only saves 5 rows of settings:

[Email protected] ~]# histsize=5

View:

[Email protected] ~]# history

562 History

563 history=5

564 History

565 histsize=5

566 history

or modify it in the following ways:

[Email protected] ~]# export history=50

[Email protected] ~]# history

564 History

565 histsize=5

566 history

567 Export HISTORY=50

568 history

(Has been deleted)

The history is also stored in the history file to view and modify the history file:

[email protected] ~]# cat ~/.bash_history

[Email protected] ~]# histfilesize=5

To empty the existing history, use the- C parameter:

[Email protected] ~]# history

569 Cat ~/.bash

570 Cat ~/.bash_history

571 histfilesize=5

572 Cat ~/.bash_history

573 history

[Email protected] ~]# history-c

[Email protected] ~]# history

570 History

Or just delete a row, with-D:

[Email protected] ~]# history

570 History

571 echo 123456|passwd--stdin Keke

572 history

[Email protected] ~]# history-d 571

[Email protected] ~]# history

570 History

571 History

572 history-d 571

573 history

To enlarge the server file descriptor:

The file descriptor is basically an integer number (0-65535),

The process uses a file descriptor that uses it to open the file and identifies the open file

To view the default file descriptor:

[Email protected] ~]# ulimit-n

1024

Adjust file descriptors: (Modify shell resource limits)

[Email protected] ~]# Ulimit-shn 65535

[Email protected] ~]# ulimit-n

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Character set modification, Linux time synchronization, tuning file descriptors