uptimeとlast reboot

linuxシステムのuptimeコマンドは、主にホストの実行時間やlinuxシステムの負荷などの情報を取得するために使用されます.uptimeコマンドは、システムがどのくらい稼働しているかを表示します.情報は、現在時間、システムがどのくらい稼働しているか、現在ユーザーにログインしているか、システムが過去1分、5分、15分以内の平均負荷の順です.uptimeコマンドの使い方は簡単です.uptimeを直接入力すればいいです.バージョンをクエリーするためのパラメータ-Vもあります.(注:大文字v)[linux@localhost]$uptime–V procps version 3.2.7[linux@localhost]$uptime表示結果:10:19:04 up 257 days,18:56,12 users,load average:2.10,2.10,2.09表示内容説明:10:19:04//システム現在時刻up 257 days,18:56//ホストが稼働時間が大きいほど、あなたの機械が安定していることを示しています.12 user//ユーザー接続数は、ユーザー数load average//システム平均負荷ではなく、総接続数です.最近の1、5、15分のシステム平均負荷を統計すると、システム平均負荷とは何ですか.システム平均負荷とは、特定の時間間隔で実行されるキュー内の平均プロセス数です.CPUコアあたりの現在のアクティブプロセス数が3以下であれば、システムのパフォーマンスは良好です.各CPUコアのタスク数が5より大きい場合、このマシンのパフォーマンスに深刻な問題があります.もしあなたのlinuxホストが1つのデュアルコアCPUであれば、Load Averageが6のとき、機械が十分に使用されていることを示します.
 
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last

NAME


       last, lastb - show listing of last logged in users

SYNOPSIS

last
 [-R
] [-
num
] [ -n
 num
 ] [-adiox
] [ -f
 file
 ] [ -t
 YYYYMMDDHHMMSS
 ] [name...
]  [tty...
]
lastb
 [-R
] [-
num
] [ -n
 num
 ] [ -f
 file
 ] [-adiox
] [name...
]  [tty...
]

DESCRIPTION

Last
  searches  back  through the file /var/log/wtmp
 (or the file designated by the -f
 flag) and dis-

       plays a list of all users logged in (and out) since that file was created.  Names of users and  tty's

       can  be given, in which case last
 will show only those entries matching the arguments.  Names of ttys

       can be abbreviated, thus last
 0
 is the same as last
 tty0
.


       When last
 catches a SIGINT signal (generated by the interrupt key, usually control-C)  or  a  SIGQUIT

       signal (generated by the quit key, usually control-/), last
 will show how far it has searched through

       the file; in the case of the SIGINT signal last
 will then terminate.


       The pseudo user reboot
 logs in each time the system is rebooted.  Thus last
 reboot
 will show a log of

       all reboots since the log file was created.

Lastb
  is  the  same  as last
, except that by default it shows a log of the file /var/log/btmp
, which

       contains all the bad login attempts.

OPTIONS

-
num
   This is a count telling last
 how many lines to show.

-n
 num
 The same.

-t
 YYYYMMDDHHMMSS


              Display the state of logins as of the specified time.  This is useful, e.g., to determine eas-

              ily  who  was  logged in at a particular time -- specify that time with -t
 and look for "still

              logged in".

-f
 file


              Specifies a file to search other than /var/log/wtmp
.

-R
     Suppresses the display of the hostname field.

-a
     Display the hostname in the last column. Useful in combination with the next flag.

-d
     For non-local logins, Linux stores not only the host name of the remote host but its IP number

              as well. This option translates the IP number back into a hostname.

-i
     This  option  is like -d
 in that it displays the IP number of the remote host, but it displays

              the IP number in numbers-and-dots notation.

-o
     Read an old-type wtmp file (written by linux-libc5 applications).

-x
     Display the system shutdown entries and run level changes.

NOTES


       The files wtmp
 and btmp
 might not be found. The system only logs information in these files  if  they

       are  present. This is a local configuration issue. If you want the files to be used, they can be cre-

       ated with a simple touch(1)
 command (for example, touch
 /var/log/wtmp
).

FILES


       /var/log/wtmp

       /var/log/btmp

AUTHOR


       Miquel van Smoorenburg, miquels AT 
cistron.nl


SEE
 ALSO

shutdown(8)
, login(1)
, init(8)


-----------------

last reboot