1. Modify the host name; View host name:
[root@ccw ~]# hostname -i fe80::6917:8a7b:dcb7:d4db%ens160 192.168.186.128 192.168.122.1 [root@ccw ~]# hostnamectl set-hostname ctt [root@ccw ~]# su - [root@ctt ~]#
First, enter hostname -i and wait for a period of time. The following IP will appear: fe80::6917:8a7b:dcb7:d4db%ens160 192.168.186.128 192.168.122.1
Then we enter: hostnamectl set hostname + the host name we want to modify. After we modify it, it will not display the host name we have modified. We need to shut down and restart to display the host name we have changed
Command for shutdown and restart:
reboot
poweroff
halt
Shutdown: shutdown using time node
-H, --halt Halt the machine. -P, --poweroff Power-off the machine (the default). -r, --reboot Reboot the machine.
2. View date:
Requirement: use fixed format to output date YY MM DD HH: mm: SS
We can enter date to find the current date Week year time (time can be accurate to seconds)
[root@ccw ~]# date Fri Nov 5 22:05:19 CST 2021
The date command is used to display or set the system time and date. The syntax format is: "date [+ specified format]".
So we can edit our time according to the table below
The following is the time we need to output according to the format. Here I expand it by adding the number of days in the week, quarter and AM/PM.
[root@ccw ~]# Date "+% Y -% m -% d% H:% m:% s% a, quarter% q, day% j,% p" 2021-11-05 22:15:45 Friday,Q4,Day 309,PM
3. Next, we will use Xshell to output "We are learning RHCSA"
Xshell has several ways to output statements:
[root@ccw ~]# echo We are learning RHCSA We are learning RHCSA [root@ccw ~]# echo "We are learning RHCSA" We are learning RHCSA [root@ccw ~]# printf "We are learning RHCSA" We are learning RHCSA[root@ccw ~]# printf "We are learning RHCSA\n" We are learning RHCSA [root@ccw ~]# echo -n "We are learning RHCSA" We are learning RHCSA[root@ccw ~]#
We can see from the above program that we can use echo and printf to output statements, but the difference is that echo can automatically wrap lines after the statement is output, while printf cannot. However, we can add line wrap after the statement like editing C language, and echo -n can prevent the statement from wrapping lines automatically, To learn more about how to use echo, you can enter man echo to find more ways to use it.
4. Use timedatectl to view the time status
List all known time zones
Modify the time zone to one of the listed time zones
[root@ccw ~]# timedatectl status Local time: Fri 2021-11-05 22:35:17 CST Universal time: Fri 2021-11-05 14:35:17 UTC RTC time: Fri 2021-11-05 14:35:17 Time zone: Asia/Shanghai (CST, +0800) System clock synchronized: yes NTP service: active RTC in local TZ: no [root@ccw ~]# timedatectl list-timezones Africa/Abidjan Africa/Accra Africa/Addis_Ababa Africa/Algiers Africa/Asmara Africa/Bamako Africa/Bangui Africa/Banjul Africa/Bissau Africa/Blantyre Africa/Brazzaville Africa/Bujumbura Africa/Cairo Africa/Casablanca Africa/Ceuta Africa/Conakry Africa/Dakar Africa/Dar_es_Salaam Africa/Djibouti Africa/Douala Africa/El_Aaiun Africa/Freetown Africa/Gaborone Africa/Harare Africa/Johannesburg Africa/Juba Africa/Kampala Africa/Khartoum Africa/Kigali Africa/Kinshasa Africa/Lagos Africa/Libreville Africa/Lome Africa/Luanda Africa/Lubumbashi Africa/Lusaka Africa/Malabo Africa/Maputo Africa/Maseru Africa/Mbabane Africa/Mogadishu Africa/Monrovia Africa/Nairobi Africa/Ndjamena Africa/Niamey Africa/Nouakchott Africa/Ouagadougou Africa/Porto-Novo Africa/Sao_Tome Africa/Tripoli Africa/Tunis Africa/Windhoek America/Adak America/Anchorage America/Anguilla America/Antigua America/Araguaina America/Argentina/Buenos_Aires America/Argentina/Catamarca America/Argentina/Cordoba America/Argentina/Jujuy America/Argentina/La_Rioja America/Argentina/Mendoza America/Argentina/Rio_Gallegos America/Argentina/Salta America/Argentina/San_Juan America/Argentina/San_Luis America/Argentina/Tucuman America/Argentina/Ushuaia America/Aruba America/Asuncion America/Atikokan America/Bahia America/Bahia_Banderas America/Barbados America/Belem America/Belize America/Blanc-Sablon America/Boa_Vista America/Bogota America/Boise America/Cambridge_Bay America/Campo_Grande America/Cancun America/Caracas America/Cayenne America/Cayman America/Chicago America/Chihuahua America/Costa_Rica America/Creston America/Cuiaba America/Curacao America/Danmarkshavn America/Dawson America/Dawson_Creek America/Denver America/Detroit America/Dominica America/Edmonton America/Eirunepe America/El_Salvador America/Fort_Nelson America/Fortaleza America/Glace_Bay America/Godthab America/Goose_Bay America/Grand_Turk America/Grenada America/Guadeloupe America/Guatemala America/Guayaquil America/Guyana America/Halifax America/Havana America/Hermosillo America/Indiana/Indianapolis America/Indiana/Knox America/Indiana/Marengo America/Indiana/Petersburg America/Indiana/Tell_City America/Indiana/Vevay America/Indiana/Vincennes America/Indiana/Winamac America/Inuvik America/Iqaluit America/Jamaica America/Juneau America/Kentucky/Louisville America/Kentucky/Monticello America/Kralendijk America/La_Paz America/Lima America/Los_Angeles America/Lower_Princes America/Maceio America/Managua America/Manaus America/Marigot America/Martinique America/Matamoros America/Mazatlan America/Menominee America/Merida America/Metlakatla America/Mexico_City America/Miquelon America/Moncton America/Monterrey America/Montevideo America/Montserrat America/Nassau America/New_York America/Nipigon America/Nome America/Noronha America/North_Dakota/Beulah America/North_Dakota/Center America/North_Dakota/New_Salem America/Ojinaga America/Panama America/Pangnirtung America/Paramaribo America/Phoenix America/Port-au-Prince America/Port_of_Spain America/Porto_Velho America/Puerto_Rico America/Punta_Arenas America/Rainy_River America/Rankin_Inlet America/Recife America/Regina America/Resolute America/Rio_Branco America/Santarem America/Santiago America/Santo_Domingo America/Sao_Paulo America/Scoresbysund America/Sitka America/St_Barthelemy America/St_Johns America/St_Kitts America/St_Lucia America/St_Thomas America/St_Vincent America/Swift_Current America/Tegucigalpa America/Thule America/Thunder_Bay America/Tijuana America/Toronto America/Tortola America/Vancouver America/Whitehorse America/Winnipeg America/Yakutat America/Yellowknife Antarctica/Casey Antarctica/Davis Antarctica/DumontDUrville Antarctica/Macquarie Antarctica/Mawson Antarctica/McMurdo Antarctica/Palmer Antarctica/Rothera Antarctica/Syowa Antarctica/Troll Antarctica/Vostok Arctic/Longyearbyen Asia/Aden Asia/Almaty Asia/Amman Asia/Anadyr Asia/Aqtau Asia/Aqtobe Asia/Ashgabat Asia/Atyrau Asia/Baghdad Asia/Bahrain Asia/Baku Asia/Bangkok Asia/Barnaul Asia/Beirut Asia/Bishkek Asia/Brunei Asia/Chita Asia/Choibalsan Asia/Colombo Asia/Damascus Asia/Dhaka Asia/Dili Asia/Dubai Asia/Dushanbe Asia/Famagusta Asia/Gaza Asia/Hebron Asia/Ho_Chi_Minh Asia/Hong_Kong Asia/Hovd Asia/Irkutsk Asia/Jakarta Asia/Jayapura Asia/Jerusalem Asia/Kabul Asia/Kamchatka Asia/Karachi Asia/Kathmandu Asia/Khandyga Asia/Kolkata Asia/Krasnoyarsk Asia/Kuala_Lumpur Asia/Kuching Asia/Kuwait Asia/Macau Asia/Magadan Asia/Makassar Asia/Manila Asia/Muscat Asia/Nicosia Asia/Novokuznetsk Asia/Novosibirsk Asia/Omsk Asia/Oral Asia/Phnom_Penh Asia/Pontianak Asia/Pyongyang Asia/Qatar Asia/Qostanay Asia/Qyzylorda Asia/Riyadh Asia/Sakhalin Asia/Samarkand Asia/Seoul Asia/Shanghai Asia/Singapore Asia/Srednekolymsk Asia/Taipei Asia/Tashkent Asia/Tbilisi Asia/Tehran Asia/Thimphu Asia/Tokyo Asia/Tomsk Asia/Ulaanbaatar Asia/Urumqi Asia/Ust-Nera Asia/Vientiane Asia/Vladivostok Asia/Yakutsk Asia/Yangon Asia/Yekaterinburg Asia/Yerevan Atlantic/Azores Atlantic/Bermuda Atlantic/Canary Atlantic/Cape_Verde Atlantic/Faroe Atlantic/Madeira Atlantic/Reykjavik Atlantic/South_Georgia Atlantic/St_Helena Atlantic/Stanley Australia/Adelaide Australia/Brisbane Australia/Broken_Hill Australia/Currie Australia/Darwin Australia/Eucla Australia/Hobart Australia/Lindeman Australia/Lord_Howe Australia/Melbourne Australia/Perth Australia/Sydney Europe/Amsterdam Europe/Andorra Europe/Astrakhan Europe/Athens Europe/Belgrade Europe/Berlin Europe/Bratislava Europe/Brussels Europe/Bucharest Europe/Budapest Europe/Busingen Europe/Chisinau Europe/Copenhagen Europe/Dublin Europe/Gibraltar Europe/Guernsey Europe/Helsinki Europe/Isle_of_Man Europe/Istanbul Europe/Jersey Europe/Kaliningrad Europe/Kiev Europe/Kirov Europe/Lisbon Europe/Ljubljana Europe/London Europe/Luxembourg Europe/Madrid Europe/Malta Europe/Mariehamn Europe/Minsk Europe/Monaco Europe/Moscow Europe/Oslo Europe/Paris Europe/Podgorica Europe/Prague Europe/Riga Europe/Rome Europe/Samara Europe/San_Marino Europe/Sarajevo Europe/Saratov Europe/Simferopol Europe/Skopje Europe/Sofia Europe/Stockholm Europe/Tallinn Europe/Tirane Europe/Ulyanovsk Europe/Uzhgorod Europe/Vaduz Europe/Vatican Europe/Vienna Europe/Vilnius Europe/Volgograd Europe/Warsaw Europe/Zagreb Europe/Zaporozhye Europe/Zurich Indian/Antananarivo Indian/Chagos Indian/Christmas Indian/Cocos Indian/Comoro Indian/Kerguelen Indian/Mahe Indian/Maldives Indian/Mauritius Indian/Mayotte Indian/Reunion Pacific/Apia Pacific/Auckland Pacific/Bougainville Pacific/Chatham Pacific/Chuuk Pacific/Easter Pacific/Efate Pacific/Enderbury Pacific/Fakaofo Pacific/Fiji Pacific/Funafuti Pacific/Galapagos Pacific/Gambier Pacific/Guadalcanal Pacific/Guam Pacific/Honolulu Pacific/Kiritimati Pacific/Kosrae Pacific/Kwajalein Pacific/Majuro Pacific/Marquesas Pacific/Midway Pacific/Nauru Pacific/Niue Pacific/Norfolk Pacific/Noumea Pacific/Pago_Pago Pacific/Palau Pacific/Pitcairn Pacific/Pohnpei Pacific/Port_Moresby Pacific/Rarotonga Pacific/Saipan Pacific/Tahiti Pacific/Tarawa Pacific/Tongatapu Pacific/Wake Pacific/Wallis UTC
The above content is that we entered timedatectl status to find the display status of the current time zone. We found the time zone of Asia\Shanghai. Then we entered timedatectl list timezones to find all the time zones. Then we entered timedatectl set timezone Asia/Aden to change the time zone to Asia/Aden, and then we entered timedatectl status, We found that our time zone changed to Asia/Aden.
[root@ccw ~]# timedatectl set-timezone Asia/Aden [root@ccw ~]# timedatectl status Local time: Fri 2021-11-05 17:39:41 +03 Universal time: Fri 2021-11-05 14:39:41 UTC RTC time: Fri 2021-11-05 14:39:41 Time zone: Asia/Aden (+03, +0300) System clock synchronized: yes NTP service: active RTC in local TZ: no
If the time is still incorrect, we can manually modify the system date:
[root@ccw ~]# timedatectl set-time 2021-11-05
If you want to modify the time, it is also very simple:
[root@ccw ~]# timedatectl set-time 22:50 [root@ccw ~]# date Fri Nov 5 22:50:25 CST 2021
5. Use the wget command to https://www.pearvideo.com/ Download any video from this website
We can enter WGet www.pearlvideo.com to operate.
wget command is used to download network files in the terminal command line. Its English full name is "web get", and its syntax format is "wget [parameter] website". You can download files directly from the command interface without opening the browser.
[root@ccw ~]# wget www.pearvideo.com --2021-11-05 22:52:33-- http://www.pearvideo.com/ Resolving www.pearvideo.com (www.pearvideo.com)... 203.107.47.49 Connecting to www.pearvideo.com (www.pearvideo.com)|203.107.47.49|:80... connected. HTTP request sent, awaiting response... 301 Moved Permanently Location: https://www.pearvideo.com [following] --2021-11-05 22:52:38-- https://www.pearvideo.com/ Connecting to www.pearvideo.com (www.pearvideo.com)|203.107.47.49|:443... connected. HTTP request sent, awaiting response... 200 OK Length: unspecified [text/html] Saving to: 'index.html.1' index.html.1 [ <=> ] 84.44K 27.5KB/s in 3.1s 2021-11-05 22:52:41 (27.5 KB/s) - 'index.html.1' saved [86471] [root@ccw ~]# ls anaconda-ks.cfg Downloads initial-setup-ks.cfg Public Desktop index.html Music Templates Documents index.html.1 Pictures Videos
Then we operate according to the following figure
After we transfer it to the desktop, we need to change the suffix html.1 to html, otherwise we will open the web page source code, and then click to enter the web page
6. View ip commands (multiple)
We can use #ifconfig and #ip a to find IP addresses.
#A notable feature between IP a and #ifconfig is that ifconfig only displays enabled interfaces, and IP displays whether all interfaces are enabled or disabled
[root@ccw ~]# ifconfig ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.186.128 netmask 255.255.255.0 broadcast 192.168.186.255 inet6 fe80::6917:8a7b:dcb7:d4db prefixlen 64 scopeid 0x20<link> ether 00:0c:29:ad:78:c8 txqueuelen 1000 (Ethernet) RX packets 3307 bytes 464808 (453.9 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1718 bytes 279525 (272.9 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255 ether 52:54:00:1f:36:0a txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root@ccw ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:0c:29:ad:78:c8 brd ff:ff:ff:ff:ff:ff inet 192.168.186.128/24 brd 192.168.186.255 scope global dynamic noprefixroute ens160 valid_lft 1525sec preferred_lft 1525sec inet6 fe80::6917:8a7b:dcb7:d4db/64 scope link noprefixroute valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether 52:54:00:1f:36:0a brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000 link/ether 52:54:00:1f:36:0a brd ff:ff:ff:ff:ff:ff