命令簡介：
該命令用來列出目前與過去登錄系統的用戶相關信息。指令英文原義：show listing of last logged in users
執行權限 ：有些需要特殊權限
指令所在路徑：/usr/bin/last
執行last指令時，它會讀取位於/var/log目錄下名稱為wtmp的文件，並把該給文件的內容記錄的登錄系統的用戶名單全部顯示出來。默認是顯示wtmp的記錄，btmp能顯示的更詳細，可以顯示遠程登錄，例如ssh登錄。
utmp文件中保存的是當前正在本系統中的用戶的信息。
wtmp文件中保存的是登錄過本系統的用戶的信息。
命令輸出字段介紹：
第一列：用戶名
第二列：終端位置。pts/0 (偽終端) 意味着從諸如SSH或telnet的遠程連接的用戶.tty (teletypewriter) 意味着直接連接到計算機或者本地連接的用戶
第三列：登錄ip或者內核 。如果你看見:0.0 或者什么都沒有，這意味着用戶通過本地終端連接。除了重啟活動，內核版本會顯示在狀態中。
第四列：開始時間
第五列：結束時間（still login in 還未退出 down 直到正常關機 crash 直到強制關機）
第六列：持續時間
命令語法：
last [-R] [-num] [ -n num ] [-adiowx] [ -f file ] [ -t YYYYMMDDHHMMSS ] [name...] [tty...]
命令參數：
| 參數 |
長參數 |
描敘 |
| -a |
將登錄系統的的主機名稱或IP地址，顯示在最后一行 |
|
| -d |
將IP地址轉換成主機名稱 |
|
| -f |
指定記錄文件，默認是顯示/var/log目錄下的wtmp文件的記錄，但/var/log目錄下得btmp能顯示的內容更豐富，可以顯示遠程登錄，例如ssh登錄 ，包括失敗的登錄請求。 |
|
| -i |
-i顯示特定ip登錄的情況。跟蹤用 -i顯示特定ip登錄的情況。跟蹤用 |
|
| -o |
Read an old-type wtmp file (written by linux-libc5 applications). |
|
| -n |
-n <顯示行數>或-<顯示行數> 設置顯示多少行記錄 |
|
| -w |
Display full user and domain names in the output |
|
| -R |
不顯示登入系統的主機名稱或IP（省略 hostname 的欄位） |
|
| -t |
顯示YYYYMMDDHHMMSS之前的信息 |
|
| -x |
顯示系統關閉、用戶登錄和退出的歷史 |
使用示例：
1：查看last命令的幫助信息
[root@DB-Server ~]# man last
[root@DB-Server ~]# last -h
last: invalid option -- h
Usage: last [-num | -n num] [-f file] [-t YYYYMMDDHHMMSS] [-R] [-x] [-o] [-w] [username..] [tty..]
2：顯示最后登錄系統的N條記錄
[root@DB-Server ~]#last -10
root pts/1 :0.0 Wed Dec 18 09:54 still logged in
root pts/4 :0.0 Wed Dec 18 09:43 - 09:48 (00:04)
root pts/1 :0.0 Wed Dec 18 09:43 - 09:48 (00:05)
root pts/3 192.168.103.79 Wed Dec 18 09:41 - 12:40 (02:59)
root pts/4 :0.0 Wed Dec 18 09:28 - 09:30 (00:01)
root pts/3 :0.0 Wed Dec 18 09:27 - 09:30 (00:02)
root pts/2 192.168.103.29 Wed Dec 18 09:27 still logged in
root pts/1 :0.0 Wed Dec 18 09:27 - 09:42 (00:15)
root pts/2 :0.0 Wed Dec 18 09:23 - 09:25 (00:01)
root pts/1 :0.0 Wed Dec 18 09:22 - 09:25 (00:02)
wtmp begins Wed Dec 11 03:02:17 2013
[root@DB-Server ~]# last -n 10
root pts/1 :0.0 Wed Dec 18 09:54 still logged in
root pts/4 :0.0 Wed Dec 18 09:43 - 09:48 (00:04)
root pts/1 :0.0 Wed Dec 18 09:43 - 09:48 (00:05)
root pts/3 192.168.103.79 Wed Dec 18 09:41 - 12:40 (02:59)
root pts/4 :0.0 Wed Dec 18 09:28 - 09:30 (00:01)
root pts/3 :0.0 Wed Dec 18 09:27 - 09:30 (00:02)
root pts/2 192.168.103.29 Wed Dec 18 09:27 still logged in
root pts/1 :0.0 Wed Dec 18 09:27 - 09:42 (00:15)
root pts/2 :0.0 Wed Dec 18 09:23 - 09:25 (00:01)
root pts/1 :0.0 Wed Dec 18 09:22 - 09:25 (00:02)
wtmp begins Wed Dec 11 03:02:17 2013
3：將登錄系統的主機名或IP地址顯示在最后一行
[root@DB-Server ~]# last -10 -a
root pts/1 Wed Dec 18 09:54 still logged in :0.0
root pts/4 Wed Dec 18 09:43 - 09:48 (00:04) :0.0
root pts/1 Wed Dec 18 09:43 - 09:48 (00:05) :0.0
root pts/3 Wed Dec 18 09:41 - 12:40 (02:59) 192.168.103.79
root pts/4 Wed Dec 18 09:28 - 09:30 (00:01) :0.0
root pts/3 Wed Dec 18 09:27 - 09:30 (00:02) :0.0
root pts/2 Wed Dec 18 09:27 still logged in 192.168.103.29
root pts/1 Wed Dec 18 09:27 - 09:42 (00:15) :0.0
root pts/2 Wed Dec 18 09:23 - 09:25 (00:01) :0.0
root pts/1 Wed Dec 18 09:22 - 09:25 (00:02) :0.0
wtmp begins Wed Dec 11 03:02:17 2013
4：不顯示登入系統的主機名稱或IP地址
[root@DB-Server ~]# last -10 -R
root pts/1 Wed Dec 18 09:54 still logged in
root pts/4 Wed Dec 18 09:43 - 09:48 (00:04)
root pts/1 Wed Dec 18 09:43 - 09:48 (00:05)
root pts/3 Wed Dec 18 09:41 - 12:40 (02:59)
root pts/4 Wed Dec 18 09:28 - 09:30 (00:01)
root pts/3 Wed Dec 18 09:27 - 09:30 (00:02)
root pts/2 Wed Dec 18 09:27 still logged in
root pts/1 Wed Dec 18 09:27 - 09:42 (00:15)
root pts/2 Wed Dec 18 09:23 - 09:25 (00:01)
root pts/1 Wed Dec 18 09:22 - 09:25 (00:02)
wtmp begins Wed Dec 11 03:02:17 2013
5: 指定/var/log/btmp文件，查看登錄系統的用戶相關信息
[root@DB-Server ~]# last -n 10 -f /var/log/btmp
root ssh:notty 192.168.136.163 Fri Oct 17 18:16 gone - no logout
root ssh:notty 192.168.136.163 Fri Oct 17 09:50 - 18:16 (08:26)
root ssh:notty 192.168.136.163 Fri Oct 17 09:50 - 09:50 (00:00)
root ssh:notty 192.168.40.218 Tue Jul 23 17:40 - 09:50 (450+16:10)
root ssh:notty 192.168.236.149 Sun Apr 14 01:34 - 17:40 (100+16:05)
root ssh:notty 192.168.178.147 Fri Mar 8 17:25 - 01:34 (36+08:08)
tomcat ssh:notty get185806.gfg1.e Fri Oct 26 16:48 - 17:25 (133+00:37)
root ssh:notty 192.168.193.3 Mon Oct 22 18:13 - 16:48 (3+22:34)
root ssh:notty 192.168.193.3 Mon Oct 22 18:13 - 18:13 (00:00)
devloper ssh:notty get185819.gfg1.e Wed Oct 17 17:22 - 18:13 (5+00:50)
btmp begins Thu Apr 12 14:30:06 2012
6: 將IP地址轉換成主機名稱
last -10 -d
7: 顯示YYYYMMDDHHMMSS（20150110093000）之前的信息
[root@DB-Server ~]# last -10 -t 20150110093000
root pts/2 192.168.102.186 Fri Jan 9 15:35 - 17:27 (01:52)
root pts/2 192.168.102.134 Thu Jan 8 10:25 - 12:27 (02:02)
root pts/3 192.168.125.53 Tue Jan 6 23:59 - 00:09 (00:09)
root pts/2 192.168.125.53 Tue Jan 6 23:45 - 00:09 (00:23)
root pts/3 192.168.102.88 Tue Jan 6 15:23 - 16:20 (00:57)
root pts/2 192.168.102.88 Tue Jan 6 15:08 - 17:25 (02:16)
oracle pts/1 :2.0 Tue Jan 6 15:07 still logged in
reboot system boot 2.6.32-200.13.1. Tue Jan 6 15:07 (7+20:21)
root pts/2 192.168.102.88 Tue Jan 6 14:47 - down (00:17)
oracle pts/1 :2.0 Tue Jan 6 14:46 - down (00:18)
wtmp begins Wed Apr 11 16:31:10 2012