Linux系統的ping命令是常用的網路命令，它通常用來測試與目標主機的連通性，我們經常會說“ping一下某機器，看是不是開著”、不能開啟網頁時會說“你先ping閘道器地址192.168.1.1試試”。它透過傳送ICMP ECHO_REQUEST資料包到網路主機（send ICMP ECHO_REQUEST to network hosts），並顯示響應情況，這樣我們就可以根據它輸出的資訊來確定目標主機是否可訪問（但這不是絕對的）。有些伺服器為了防止透過ping探測到，透過防火牆設定了禁止ping或者在核心引數中禁止ping，這樣就不能透過ping確定該主機是否還處於開啟狀態。
linux下的ping和windows下的ping稍有區別,linux下ping不會自動終止,需要按ctrl+c終止或者用引數-c指定要求完成的回應次數。
1.命令格式：
ping [引數] [主機名或IP地址]
2.命令功能：
ping命令用於：確定網路和各外部主機的狀態；跟蹤和隔離硬體和軟體問題；測試、評估和管理網路。如果主機正在執行並連在網上，它就對回送訊號進行響應。每個回送訊號請求包含一個網際協議（IP）和 ICMP 頭，後面緊跟一個 tim 結構，以及來填寫這個資訊包的足夠的位元組。預設情況是連續傳送回送訊號請求直到接收到中斷訊號（Ctrl-C）。
ping 命令每秒傳送一個資料包並且為每個接收到的響應列印一行輸出。ping 命令計算訊號往返時間和(資訊)包丟失情況的統計資訊，並且在完成之後顯示一個簡要總結。ping 命令在程式超時或當接收到 SIGINT 訊號時結束。Host 引數或者是一個有效的主機名或者是因特網地址。
3.命令引數：
-d 使用Socket的SO_DEBUG功能。
-f 極限檢測。大量且快速地送網路封包給一臺機器，看它的回應。
-n 只輸出數值。
-q 不顯示任何傳送封包的資訊，只顯示最後的結果。
-r 忽略普通的Routing Table，直接將資料包送到遠端主機上。通常是檢視本機的網路介面是否有問題。
-R 記錄路由過程。
-v 詳細顯示指令的執行過程。
<p>-c 數目：在傳送指定數目的包後停止。
-i 秒數：設定間隔幾秒送一個網路封包給一臺機器，預設值是一秒送一次。
-I 網路介面：使用指定的網路介面送出資料包。
-l 前置載入：設定在送出要求資訊之前，先行發出的資料包。
-p 範本樣式：設定填滿資料包的範本樣式。
-s 位元組數：指定傳送的資料位元組數，預設值是56，加上8位元組的ICMP頭，一共是64ICMP資料位元組。
-t 存活數值：設定存活數值TTL的大小。
4.使用例項：
例項1：ping的通的情況
命令：
ping 192.168.120.205
輸出：
[root@localhost ~]# ping 192.168.120.205
PING 192.168.120.205 (192.168.120.205) 56(84) bytes of data.
64 bytes from 192.168.120.205: icmp_seq=1 ttl=64 time=0.720 ms
64 bytes from 192.168.120.205: icmp_seq=2 ttl=64 time=0.181 ms
64 bytes from 192.168.120.205: icmp_seq=3 ttl=64 time=0.191 ms
64 bytes from 192.168.120.205: icmp_seq=4 ttl=64 time=0.188 ms
64 bytes from 192.168.120.205: icmp_seq=5 ttl=64 time=0.189 ms
--- 192.168.120.205 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4000ms
rtt min/avg/max/mdev = 0.181/0.293/0.720/0.214 ms
[root@localhost ~]#
例項2：ping不通的情況
命令：
ping 192.168.120.202
輸出：
[root@localhost ~]# ping 192.168.120.202
PING 192.168.120.202 (192.168.120.202) 56(84) bytes of data.
From 192.168.120.204 icmp_seq=1 Destination Host Unreachable
From 192.168.120.204 icmp_seq=2 Destination Host Unreachable
From 192.168.120.204 icmp_seq=3 Destination Host Unreachable
From 192.168.120.204 icmp_seq=4 Destination Host Unreachable
From 192.168.120.204 icmp_seq=5 Destination Host Unreachable
From 192.168.120.204 icmp_seq=6 Destination Host Unreachable
--- 192.168.120.202 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time 7005ms
, pipe 4
[root@localhost ~]#
例項3：ping閘道器
命令：
ping -b 192.168.120.1
輸出：
[root@localhost ~]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.120.0 * 255.255.255.0 U 0 0 0 eth0
192.168.0.0 192.168.120.1 255.255.0.0 UG 0 0 0 eth0
10.0.0.0 192.168.120.1 255.0.0.0 UG 0 0 0 eth0
default 192.168.120.240 0.0.0.0 UG 0 0 0 eth0
[root@localhost ~]# ping -b 192.168.120.1
PING 192.168.120.1 (192.168.120.1) 56(84) bytes of data.
64 bytes from 192.168.120.1: icmp_seq=1 ttl=255 time=2.02 ms
64 bytes from 192.168.120.1: icmp_seq=2 ttl=255 time=1.83 ms
64 bytes from 192.168.120.1: icmp_seq=3 ttl=255 time=1.68 ms
64 bytes from 192.168.120.1: icmp_seq=4 ttl=255 time=1.98 ms
64 bytes from 192.168.120.1: icmp_seq=5 ttl=255 time=1.88 ms
--- 192.168.120.1 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4000ms
rtt min/avg/max/mdev = 1.682/1.880/2.020/0.129 ms
例項4：ping指定次數
命令：
ping -c 10 192.168.120.206
輸出：
[root@localhost ~]# ping -c 10 192.168.120.206
PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
64 bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.25 ms
64 bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.260 ms
64 bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.242 ms
64 bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.271 ms
64 bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.274 ms
64 bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.295 ms
64 bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.269 ms
64 bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.270 ms
64 bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.253 ms
64 bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.289 ms
--- 192.168.120.206 ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9000ms
rtt min/avg/max/mdev = 0.242/0.367/1.251/0.295 ms
[root@localhost ~]#
例項5：時間間隔和次數限制的ping
命令：
ping -c 10 -i 0.5 192.168.120.206
輸出：
[root@localhost ~]# ping -c 10 -i 0.5 192.168.120.206
PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
64 bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.24 ms
64 bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.235 ms
64 bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.244 ms
64 bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.300 ms
64 bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.255 ms
64 bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.264 ms
64 bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.263 ms
64 bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.331 ms
64 bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.247 ms
64 bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.244 ms
--- 192.168.120.206 ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 4499ms
rtt min/avg/max/mdev = 0.235/0.362/1.241/0.294 ms
[root@localhost ~]# ping -c 10 -i 0.01 192.168.120.206
PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
64 bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=0.244 ms
64 bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.195 ms
64 bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.219 ms
64 bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.204 ms
64 bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=3.56 ms
64 bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=1.93 ms
64 bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.193 ms
64 bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.193 ms
64 bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.202 ms
64 bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.211 ms
--- 192.168.120.206 ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 90ms
rtt min/avg/max/mdev = 0.193/0.716/3.564/1.080 ms
[root@localhost ~]#
例項6：透過域名ping公網上的站點
命令：
ping -c 5 www.58.com
輸出：
peida-VirtualBox ~ # ping -c 5 www.58.com
PING www.58.com (211.151.111.30) 56(84) bytes of data.
64 bytes from 211.151.111.30: icmp_req=1 ttl=49 time=14.7 ms
64 bytes from 211.151.111.30: icmp_req=2 ttl=49 time=16.4 ms
64 bytes from 211.151.111.30: icmp_req=3 ttl=49 time=15.2 ms
64 bytes from 211.151.111.30: icmp_req=4 ttl=49 time=14.6 ms
64 bytes from 211.151.111.30: icmp_req=5 ttl=49 time=19.9 ms
--- www.58.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 20101ms
rtt min/avg/max/mdev = 14.618/16.192/19.917/1.965 ms
peida-VirtualBox ~ #
例項7：多引數使用
命令：
ping -i 3 -s 1024 -t 255 192.168.120.206
輸出：
[root@localhost ~]# ping -i 3 -s 1024 -t 255 192.168.120.206
PING 192.168.120.206 (192.168.120.206) 1024(1052) bytes of data.
1032 bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.99 ms
1032 bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.694 ms
1032 bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.300 ms
1032 bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.481 ms
1032 bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.415 ms
1032 bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.600 ms
1032 bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.411 ms
1032 bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.281 ms
1032 bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.318 ms
1032 bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.362 ms
1032 bytes from 192.168.120.206: icmp_seq=11 ttl=64 time=0.408 ms
1032 bytes from 192.168.120.206: icmp_seq=12 ttl=64 time=0.445 ms
1032 bytes from 192.168.120.206: icmp_seq=13 ttl=64 time=0.397 ms
1032 bytes from 192.168.120.206: icmp_seq=14 ttl=64 time=0.406 ms
1032 bytes from 192.168.120.206: icmp_seq=15 ttl=64 time=0.458 ms
--- 192.168.120.206 ping statistics ---
15 packets transmitted, 15 received, 0% packet loss, time 41999ms
rtt min/avg/max/mdev = 0.281/0.531/1.993/0.404 ms
[root@localhost ~]#
說明：
-i 3 傳送週期為 3秒 -s 設定傳送包的大小為1024 -t 設定TTL值為 255