有些時候Linux 系統管理員在接手一臺新的服務器時，如果沒有好的交接文檔，我們想要得到的主機信息就只能靠自己了。很多主機信息是可以直接通過命令從主機上獲得的，本文就與大家分享 5 個獲取 Linux 主機信息的命令。
此處以Ubuntu 13.04操作系統為例。
1. 查看或改變 Linux 主機名的命令
$ hostname
mylinuxbook-Inspiron-1525
從命令結果上您可以看到我的 Ubuntu 主機名是 mylinuxbook-Inspiron-1525。您可能會注意到，主機名通常也出現在命令提示符下，所以很多時候我們將主機名改短一些可能會更方便使用。
通過如下命令來改變它：
$ sudo hostname mylinuxbook
注意，改變主機名需要 root 權限，所以我在上面使用了 sudo 命令來提升權限。如果您執行了上面的命令，那么您可以立即打開一個新的終端，在終端中您就能查看到您新的主機名，同時您會看到新的名稱的命令提示符。
不過通過這個命令修改的主機名是一個臨時功能，一旦您重啟您的服務器，這個名稱將不會存在。如果您需要永久的修改主機名，那么您需要修改 /etc/hostname 文件。
2. host 命令
這個命令可以讓您來查看主機的 IP 信息，
$ host google.com
google.com has address 74.125.236.72
google.com has address 74.125.236.78
google.com has address 74.125.236.73
google.com has address 74.125.236.71
google.com has address 74.125.236.65
google.com has address 74.125.236.69
google.com has address 74.125.236.66
google.com has address 74.125.236.64
google.com has address 74.125.236.67
google.com has address 74.125.236.68
google.com has address 74.125.236.70
google.com has IPv6 address 2404:6800:4007:801::1004
google.com mail is handled by 10 aspmx.l.google.com.
google.com mail is handled by 20 alt1.aspmx.l.google.com.
google.com mail is handled by 30 alt2.aspmx.l.google.com.
google.com mail is handled by 40 alt3.aspmx.l.google.com.
google.com mail is handled by 50 alt4.aspmx.l.google.com.
從命令的運行結果我們可以看到主機的 IP （IPV4 和 IPV6）以及郵件服務器相關的信息。
如果您還想查看 DNS 記錄，可以使用 -a 參數
$ host -a google.com
Trying "google.com"
;; ->>HEADER- opcode: QUERY, status: NOERROR, id: 34210
;; flags: qr rd ra; QUERY: 1, ANSWER: 21, AUTHORITY: 0, ADDITIONAL: 0/p>
p>;; QUESTION SECTION:
;google.com. IN ANY/p>
p>;; ANSWER SECTION:
google.com. 211 IN AAAA 2404:6800:4007:800::1009
google.com. 299 IN MX 10 aspmx.l.google.com.
google.com. 299 IN MX 50 alt4.aspmx.l.google.com.
google.com. 299 IN MX 20 alt1.aspmx.l.google.com.
google.com. 299 IN MX 30 alt2.aspmx.l.google.com.
google.com. 299 IN MX 40 alt3.aspmx.l.google.com.
google.com. 267 IN A 74.125.236.168
google.com. 267 IN A 74.125.236.165
google.com. 267 IN A 74.125.236.166
google.com. 267 IN A 74.125.236.167
google.com. 267 IN A 74.125.236.164
google.com. 267 IN A 74.125.236.174
google.com. 267 IN A 74.125.236.163
google.com. 267 IN A 74.125.236.169
google.com. 267 IN A 74.125.236.162
google.com. 267 IN A 74.125.236.161
google.com. 267 IN A 74.125.236.160
google.com. 136467 IN NS ns3.google.com.
google.com. 136467 IN NS ns1.google.com.
google.com. 136467 IN NS ns4.google.com.
google.com. 136467 IN NS ns2.google.com./p>
p>Received 412 bytes from 127.0.1.1#53 in 30 ms
如果您需要查看域名服務器或者 SOA 信息，可以使用 -C 參數
$ host -C google.com
Nameserver 216.239.38.10:
google.com has SOA record ns1.google.com. dns-admin.google.com. 2013061800 7200 1800 1209600 300
Nameserver 216.239.34.10:
google.com has SOA record ns1.google.com. dns-admin.google.com. 2013061800 7200 1800 1209600 300
Nameserver 216.239.36.10:
google.com has SOA record ns1.google.com. dns-admin.google.com. 2013061800 7200 1800 1209600 300
Nameserver 216.239.32.10:
google.com has SOA record ns1.google.com. dns-admin.google.com. 2013061800 7200 1800 1209600 300
或者您可以使用 -d 或者 -v 參數來輸出詳細信息
$ host -v google.com
Trying "google.com"
;; ->>HEADER- opcode: QUERY, status: NOERROR, id: 52674
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 0, ADDITIONAL: 0/p>
p>;; QUESTION SECTION:
;google.com. IN A/p>
p>;; ANSWER SECTION:
google.com. 77 IN A 74.125.236.40
google.com. 77 IN A 74.125.236.38
google.com. 77 IN A 74.125.236.34
google.com. 77 IN A 74.125.236.37
google.com. 77 IN A 74.125.236.36
google.com. 77 IN A 74.125.236.41
google.com. 77 IN A 74.125.236.35
google.com. 77 IN A 74.125.236.33
google.com. 77 IN A 74.125.236.46
google.com. 77 IN A 74.125.236.32
google.com. 77 IN A 74.125.236.39/p>
p>Received 204 bytes from 127.0.1.1#53 in 33 ms
Trying "google.com"
;; ->>HEADER- opcode: QUERY, status: NOERROR, id: 31473
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0/p>
p>;; QUESTION SECTION:
;google.com. IN AAAA/p>
p>;; ANSWER SECTION:
google.com. 28 IN AAAA 2404:6800:4007:800::1002/p>
p>Received 56 bytes from 127.0.1.1#53 in 28 ms
Trying "google.com"
;; ->>HEADER- opcode: QUERY, status: NOERROR, id: 2871
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 0/p>
p>;; QUESTION SECTION:
;google.com. IN MX/p>
p>;; ANSWER SECTION:
google.com. 13 IN MX 40 alt3.aspmx.l.google.com.
google.com. 13 IN MX 50 alt4.aspmx.l.google.com.
google.com. 13 IN MX 10 aspmx.l.google.com.
google.com. 13 IN MX 20 alt1.aspmx.l.google.com.
google.com. 13 IN MX 30 alt2.aspmx.l.google.com./p>
p>Received 136 bytes from 127.0.1.1#53 in 29 ms
這個命令可以讓您獲得大量的主機信息。
3. Arch 命令
這個命令可以讓您得到系統的處理器系統構架信息：
$ arch
x86_64
從命令執行結果來看，我的主機是 64 位的 x86 系列處理器。
4. uname 命令
上面的 arch 只能得到系統的簡單信息，如果想得到更多的信息，我們就需要使用 uname 命令了，uname 命令可以獲取到操作系統名稱、內核名稱、內核版本、主機名、網絡節點等信息。
使用 -o 參數來查看操作系統名稱：
$ uname -o
GNU/Linux
使用 -s 參數來查看內核名稱：
$ uname -s
Linux
使用 -m 參數來查看系統構架信息，這個參數的得到的結果和上面的 arch 是一樣的：
$ uname -m
x86_64
還有如下命令您可以試一試：
$ uname -n
linuxuser-laptop
$ uname -r
2.6.32-21-generic
$ uname -v
#33-Ubuntu SMP Fri Apr 18 08:09:38 UTC 2011
5. dig 命令
dig 命令是 DNS 查看工具，使用此命令可以查看域名服務器的主機地址
$ dig google.com/p>
p>; >> DiG 9.9.2-P1 >> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER- opcode: QUERY, status: NOERROR, id: 40090
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 0, ADDITIONAL: 1/p>
p>;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;google.com. IN A/p>
p>;; ANSWER SECTION:
google.com. 227 IN A 74.125.236.33
google.com. 227 IN A 74.125.236.38
google.com. 227 IN A 74.125.236.46
google.com. 227 IN A 74.125.236.40
google.com. 227 IN A 74.125.236.32
google.com. 227 IN A 74.125.236.37
google.com. 227 IN A 74.125.236.34
google.com. 227 IN A 74.125.236.35
google.com. 227 IN A 74.125.236.41
google.com. 227 IN A 74.125.236.39
google.com. 227 IN A 74.125.236.36/p>
p>;; Query time: 30 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Sat Jun 22 15:38:58 2013
;; MSG SIZE rcvd: 215
