如何正确显示utmp、wtmp、btmp文件的内容？

Question

如何使用 cat显示/var/run/utmp, /var/log/wtmp, /var/log/btmp。当我试图显示它们时，我也得到了一些其他字符。这是我尝试读取文件时得到的输出：

jai@frank-Jai:~$ cat /var/run/utmp
~~~reboot3.8.0-26-genericf?Q%p  2~~~runlevel3.8.0-26-genericf?Q
?   ?tty44LOGIN?f?Q?tty55LOGIN?f?Q?tty22LOGIN?f?Q?tty33LOGIN?f?Q?tty66LOGIN?f?Q?tty11LOGIN?k?Qtty7:0jai:0y?Q
                                                       ??pts/0/0jai:0.0?{?QFQjai@frank-Jai:~$ cat /var/log/wtmp
~~~reboot3.8.0-19-generic??Q?b
2~~~runlevel3.8.0-19-generic??Q?c
*tty44LOGIN*??Q0tty55LOGIN0??Q:tty22LOGIN:??Q;tty33LOGIN;??Q=tty66LOGIN=??Q"tty11LOGIN"??Q?pts/1/1jai:0.0??Q?D       pts/1/1jai??Q???   pts/1/1jai:0.0t??Q??    pts/2/2jai:0.0???Q
?   pts/3/3jai:0.0`??Qpts/3/3jaib??Qpts/1/1jai"??Q
                                                        pts/2/2jai"??Q62~~~ru*tty44*;??Q?0tty550;??Q?:tty22:;??Q?;tty33;;??QM=tty66=;??Q?
                                                                       "tty11";??Ql,~~~shutdown3.8.0-19-genericH??Qz?~~~reboot3.8.0-26-generic???Q-?2~~~runlevel3.8.0-26-generic???Q?ctty44LOGINc???Qjtty55LOGINj???Qutty22LOGINu???Qvtty33LOGINv???Qytty66LOGINy???Q?tty11LOGIN????Q02~~~runlevel3.8.0-26-generic???Q.
                 ctty44c???Qjtty55j???Qutty22u???Qvtty33v???Qytty66y???Q?tty11????Q?~~~shutdown3.8.0-26-generic???Q?~~~reboot3.8.0-26-generic??stty44LOGINs??Qztty55LOGINz??Q?tty22LOGIN???Qtty33LOGIN??Q?tty66LOGIN???QCtty11LOGINC??Qpts/0/0jai:0.0B??Qp?
                                            pts/1/1jai:0.0??QOpts/1/1jai??Q(C
                                                                             ptspts/1/1jai??Q"pts/0/0jai;?Q?
stty44s?A?Q??ztty55z?A?Q??i?tty22??A?Q??ntty33?A?QZ?26-ge?tty66??A?Qmn
Ctty11C?A?Qz
~~~shutdown3.8.0-26-generic?A?Q
                                ?~~~reboot3.8.0-26-generic e?Q?2~~~runlevel3.8.0-26-generic e?Q?iMtty44LOGINM e?QStty55LOGINS e?Q]tty22LOGIN] e?Q^tty33LOGIN^ e?Q`tty66LOGIN` e?Q?tty11LOGIN?#e?QL
pts/0/0jai:0.0l?Q?#
pts/0/0jai:0.0:t?Q#;pts/0/0jai??QO|02~~~runlevel3.8.0-26-generic??Qu?Mtty44M??QStty55S??Q]tty22]??Q^tty33^??Q`tty66`??Q?    ?tty11???Q?D    ~~~shutdown3.8.0-26-generic???Q
                        ~~~reboot3.8.0-26-generic???Q?2~~~runlevel3.8.0-26-generic???Q[?ktty44LOGINk???Qqtty55LOGINq???Q{tty22LOGIN{???Q|tty33LOpts/2/2jaiL??Q??62~~~runlevel3.8.0-26-genericL??Q??ktty44kL??Qqtty55qL??Q{tty22{L??QY   |tty33|L??Q@
                               ?tty66?L??Q? ?tty11?L??Q?M   ~~~shutdown3.8.utty44LOGINuW??Q}tty55LOGIN}W??Qtty22LOGINW??Q?tty33LOGIN?W??Q?tty66pts/0/0jai:0.0???Qpts/0/0jaiv??Ql?02~~~runlevel3.8.0-26-genericv??Q?butty44uv??Q1
    }tty55}v??Q4
                tty22v??Q*

                         ?tty33?v??Q&
                                      ?tty66?v??Q3
                                                    ?tty11?v??Q?
                                                                   ~~~shutdown3.8.0-26-generic???QN%~~~reboot3.8.0-26-generic???Q
y2~~~runlevel3.8.0-26-generic???Q??tty44LOGIN???Q?tty55LOGIN????Q?tty22LOGIN????Q?tty33LOGIN????Q?tty66LOGIN????Q?tty11LOGIN????Q02~~~runleveltty44]??Q??tty55?]??Q??tty22?]??Q??tty33?]??Q??tty66?]??QE?tty11?]??Q??~~~shutdown3.8.0-26-genericj??Q?Q~~~reboot3.8.0-26-genericC??QQ?
                                                                    2~~~runleveltty44LOGINlC??Qptty55LOGINpC??Qvtty22LOGINvC??Qwtty33LOGINwD??Qytty66LOGINyD??Q?tty11LOGIN?E??Q62~~~runlevel3.8.0-26-generice??Qltty44lf??Q
)ptty55pf??Q4vtty22vf??Q?7wtty33wf??Q?=ytty66yf??Q?B?tty11?f??Q?^~~~shutdown3.8.0-26-generics??Q
~~~reboot3.8.0-26-genericZ??Q?2~~~runlevel3.8.0-26-genericZ??Q??tty44LOGINZ??Q?tty55LOGIN?Z??Q?tty22LOGIN?Z??Q?tty33LOGIN?Z??Q?tty66LOGIN?Z??Q?tty11LOGIN?[??Q62~~~runlevel3.8.0-26-generich??QCtty44h??Q ?tty55?h??Qm?tty22?h??Q9?tty33?h??Q??tty66?h??Q?tty11?h??Q??~~~shutdown3.8.0-26-generick??Q5~~~reboot3.8.0-26-generic??Q?>2~~~runlevel3.8.0-26-generic??Q?4utty44LOGINu??Q{tty55LOGIN{??Q?tty22LOGIN???Q?tty33LOGIN???Q?tty66LOGIN???Q?tty11LOGIN???Q02~~~runlevel3.8.0-26-generic???Q?utty44u???Q?{tty55{???Q??tty22????Q?tty33????Q??tty66????Q?tty11????Q"~~~shutdown3.8.0-26-generic???Q(
                   ~~~reboot3.8.0-26-generic???Q=2~~~runlevel3.8.0-26-generic???Q?;etty44LOGINe???Qjtty55LOGINj???Qttty22LOGINt???Qztty33LOGINz???Q?tty66LOGIN????Q?tty11LOGIN????Q?pts/0/0jai:0.0[j?QE5
                                                            pts/0/0jai?m?Q?pts/0/0jai:0.0?m?Q?pts/0/0jain?Q??62~~~runlevel3.8.0-26-generic0n?Q??etty44e0n?Qjtty55j0n?Q?       ttty22t0n?Q
                                    ?  ztty33z0n?Q'? ?tty66?0n?Q@? ?tty11?0n?Qu?    ~~~shutdown3.8.0-26-generic>n?Q??~~~reboot3.8.0-26-generic?+?Q?S2~~~runlevel3.8.0-26-generic?+?Q?{tty44LOGIN{?+?Q?tty55LOGIN??+?Q?tty22LOGIN??+?Q?tty33LOGIN??+?Q?tty66LOGIN??+?Q?tty11LOGIN??+?Qk  pts/0/0jai:0.0<,?Qpts/0/0jaih??Qv?
                  62~~~runlevel3.8.0-26-generic??Q??{tty44{??QT
?tty55???Q@U
              ?tty22???QPW
                            ?tty33???QIY
                                          ?tty66???QV[
                                                        ?tty11???Q?j
                                                                       ~~~shutdown3.8.0-26-generic?Q~~~reboot3.8.0-26-generic?_?Q??2~~~runlevel3.8.0-26-generic?_?Q9bhtty44LOGINh?_?Qltty55LOGINl?_?Qtty22LOGIN?_?Q?tty33LOGIN??_?Q?tty66LOGIN??_?Q?tty11LOGIN??_?Q02~~~runlevel3.8.0-26-generic?_?Q@htty44h?_?Q?ltty55l?_?QJtty22?_?Q+?tty33??_?Q??tty66??_?Q??tty11??_Y~~~shutdown3.8.0-26-generic?_?Qc?~~~reboot3.8.0-26-generic???Q?D2~~~runlevel3.8.0-26-generic???Q7yktty44LOGINk???Qstty55LOGINs???Q?tty22LOGIN????Q?tty33LOGIN????Q?tty66LOGIN????Q?tty11LOGIN????QG
                                                            pts/0/0jai:0.0?-?Q??ktty44k&D?Q?stty55s&D?Q??tty22?&D?Q??tty33?&D?Q<?tty66?&D?Q4?tty11?&D?Q`e~~~shutdown3.8.0-26-generic)D?Q?m
~~~reboot3.8.0-26-generic?Q&?2~~~runlevel3.8.0-26-generic?Q?4ktty44LOGINk?Qptty55LOGINp?Q{tty22LOGIN{?Q|tty33LOGIN|?Q~tty66LOGIN~?Q?tty11LOGIN??h?Q02~~~runlevel3.8.0-26-generic?k?Q?1
                                            ktty44k?k?Q?ptty55p?k?Q?{tty22{?k?Q?|tty33|?k?Q~tty66~?k?Q?tty11??k?Q?~~~shutdown3.8.0-26-generic?k?Q?~~~reboot3.8.0-26-generic???Q|2~~~runlevel3.8.0-26-generic???Q3?tty44LOGIN????Qtty55LOGIN???Q?tty22LOGIN????Q?tty33LOGIN????Q?tty66LOGIN????Q?tty11LOGIN????Qo
?tty44????Qtty55????tty22????Q??tty33????Q??tty66????Q??tty11????Q??~~~shutdown3.8.0-26-generic???Qm?
                                 ~~~reboot3.8.0-26-generic?Q?2~~~runlevel3.8.0-26-generic?Q*?ptty44LOGINp?Qvtty55LOGINv?Q?tty22LOGIN??Q?tty33LOG?tty44LOGIN?Qv?Q?tty55LOGIN?Qv?Q?tty22LOGIN?Qv?Q?tty33LOGIN?Qv?Q?t0#pts/4/4jai:0.0??Qt`?)pts/1/1root:0.0%??Qpts/1/1root~??Q'1pts/4/4jai???Q?02?tty44?i??Q???tty55?i??Q?tty22?i??Q?tty33?i??Q?tty66?i??Q?tty11?i??Q~~~shutdown3.8.0-26-genericy??Q??~~~reboot3.8.0-26-generic???Q<2~~~runlevel3.8.0-26-generic???Q?Yotty44LOGINo???Qttty55LOGINt???Qztty22LOGINz???Q{tty33LOGIN{???Qtty66LOGIN???Q?tty11LOGIN????Q?
                                                          pts/0/0jai:0.0P(?QDhpts/0/0jaiN*?Q??
              02~~~runlevel3.8.0-26-generic7>?Q?
                                               otty44o8>?Q?ttty55t8>?Q?ztty22z8>?Q?{tty33{8>?Q5tty668>?Q7?tty11?8>?Qk?~~~shutdown3.8.0-26-genericG>?Q?F~~~reboot3.8.0-26-generic???QZ<2~~~runlevel3.8.0-26-generic???Q?%Ptty44LOGINP???QTtty55LOGINT???QZtty22LOGINZ???Q[tty33LOGIN[???Q^tty66~~~shutdown3.8.0-26-generic??Q??~~~reboot3.8.0-26-generict??Q(sy44P??Q?%
2~~~runlevel3.8.0-26-generict??Q?3
                                   Ptty44LOGINPt??QTtty55LOGINTt??QZtty22LOGINZt??Q[tty33LOGIN[t??Q^tty66LOGIN^t??Q?tty11LOGIN?v??Q?pts/0/0jai:0.0???Qb?pts/1/1jai:0.0???Q??pts/0/0jai???Q??pts/1/1jai???Q?02~~~runlevel3.8.0-26-genericU??Q$:
                Ptty44PV??QTtty55TV??Q?Ztty22ZV??Q[tty33[V??^tty66^V??Q?tty11?V??Q??~~~shutdown3.8.0-26-generice??Q?&~~~reboot3.8.0-26-genericX ?Q2~~~runlevel3.8.0-26-genericX ?Qf?Ytty44LOGINYX   ?Q]tty55LOGIN]X ?Qctty22LOGINcX ?Qetty33LOGINeX ?Qitty66LOGINiX ?Q?tty11LOGIN?Y ?Qpts/0/0jai:0.0?
?QlU                                             ?Q@?pts/1/1jai:0.0
   pts/1/1jaii?Q?L    pts/0/0jaik?Q??n(pts/0/0jai:0.0??Qpts/0/0jai?#?QB02~Ytty44Y?k?Q?(]tty55]?k?Q|1ctty22c?k?Q?Setty33e?k?Q?Witty66i?k?Q?[?tty11??k?Q7?~~~shutdown3.8.0-26-generic?k?QL?~~~reboot3.8.0-26-generic??QMG
2~~~runlevel3.8.0-26-generic??Q?
?tty44LOGIN???Q?tty55LOGIN???Q?tty22LOGIN???Q?tty33LOGIN???Q?tty66LOGIN???QEtty11LOGINE??Q? pts/1/1jai:0.0???Q?h   pts/1/1jaiW??Q.
                                                                              ?tty55?^??Q?tty22?^??Q?tty33?^??Q?tty66?^??QEtty11E^??Q?~~~shutdown3.8.0-26-genericr??Q?t~~~reboot3.8.0-26-generic??Q!Q
2~~~runlevel3.8.0-26-generic??Qy
rtty44LOGINr??Qvtty55LOGINv??Q|tty22LOGIN|??Q}tty33LOGIN}??Q?tty66LOGIN???Qxtty11LOGINx??Q? pts/1/1jai:0.0?Q??  pts/2/2jai:0.0O&?QiO
    ?   pts/3/3jai:0.0?'?Q~pts/2/2jai?,?Q/pts/3/3jai?,?Q??pts/1/1jai2?Q?%pts/?/2jai:0.0O;?Q?pts/2/2jail<?Q
 7pts/2/2jai:0.0?P?Q(w
                      7pts/4/4jai:0.0?Q?Q'?
                                          pts/2/2jai?[?Qpts/4/4jai?[?Q?i02~~~runlevel3.8.0-26-generic?]?Q?rtty44r?]?Q?
vtty55v?]?Q??
|tty22|?]?Q?
}tty33}?]?Q9?
?tty66??]?Q??
xtty11x?]?Q?
~~~shutdown3.8.0-26-generic?]?Q??~~~reboot3.8.0-26-generic^?Q|? 2~~~runlevel3.8.0-26-generic^?Q??   ?tty44LOGIN?^?Q?tty55LOGIN?^?Q?tty22LOGIN?^?Q?tty33LOGIN?^?Q?tty66LOGIN?^?Q?tty11LOGIN?^?Q  
                                                                pts/1/1jai:0.0?b?Qpts/1/1jai?c?Q?
62~~~runlevel3.8.0-26-generic?c?Q??tty44??c?Q5?tty55??c?Q??tty22??c?Q??tty33??c?Q??tty66??c?Q?tty11??c?Q##~~~shutdown3.8.0-26-generic
                                                                   d?Q?~~~reboot3.8.0-26-genericI}?Q?
2~~~runlevel3.8.0-26-genericI}?Q5<
                                   ?tty44LOGIN?I}?Q?tty55LOGIN?I}?Q?tty22LOGIN?I}?Q?tty33LOGIN?I}?Q?tty66LOGIN?I}?Q?tty11LOGIN?P}?Q~~~reboot3.8.0-26-generic1??Q?2~~~runlevel3.8.0-26-generic1??Q6?tty44LOGIN?1??Q?tty55LOGIN?1??Q?tty22LOGIN?1??Q?tty33LOGIN?1??Q?tty66LOGIN?1??Qtty11LOGIN6??QLpts/1/1jai:0.05*?Q??
                      pts/1/1jai?+?Q1m&pts/0/0jai:0.0?4?pts/0/0jai?5?Q??02~~~runlevel3.8.0-26-generic=?Qq#?tty44?=?Q?.
                                          ?tty55?=?Q?1
                                                       ?tty22?=?QD4
                                                                    ?tty33?=?Q?6
 ?tty66?=?9
            tty11=?Q$F
                      ~~~shutdown3.8.0-26-generic=?Q??~~~shutdown3.8.0-26-generic=?Q?%~~~reboot3.8.0-26-generic}??Q)|   2~~~runlevel3.8.0-26-generic}??Q4D
?tty44LOGIN?}??Q?tty55LOGIN?}??Q?tty22LOGIN?}??Q?tty33LOGIN?}??Q?tty66LOGIN?}??Qtty11LOGIN???Q? pts/1/1jai:0.0V??Qpts/1/1jai6??QT?~~~reboot3.8.0-26-generic=??Q2~~~runlevel3.8.0-26-generic=??Q:P   ?tty44LOGIN?=??Q?tty55LOGIN?=??Qtty22LOGIN=??Qtty33LOGIN=??Q?tty66LOGIN?=??Q?tty11LOGIN?C??Q02~~~runlevel3.8.0-26-generic???Q??tty44????Q?tty55????Q>tty22???Qtty33???Q~~~shutdown3.8.0-26-generic???Ql?~~~reboot3.8.0-26-genericf?Q%p  2~~~runlevel3.8.0-26-genericf?Q
?   ?tty44LOGIN?f?Q?tty55LOGIN?f?Q?tty22LOGIN?f?Q?tty33LOGIN?f?Q?tty66LOGIN?f?Q?tty11LOGIN?k?Q?pts/0/0jai:0.0?{?QFQjai@frank-Jai:~$ 



jai@frank-Jai:~$ sudo cat /var/log/btmp

Answer 1

您要读取的所有三个文件都以二进制格式存储。它们不是纯文本文件，无法使用普通文本编辑器或使用命令来读取cat。正如您所指出的，这样做会导致输出乱码。

下面分别介绍这三个文件的功能：

• 该文件/var/log/btmp记录失败的登录尝试。
• 该文件/var/run/utmp允许人们发现有关谁当前正在使用该系统的信息。该文件将包含有关用户登录的信息：在哪些终端上、注销、系统事件和系统的当前状态、系统启动时间（由正常运行时间使用）等。
• 该文件/var/log/wtmp提供了 utmp 数据的历史记录。

您可以使用该last命令来读取每个文件。

例如：

sudo last /var/log/btmp` (note: this command needs to be run using sudo)

johndoe@computer:~$ last -f /var/run/utmp
 johndoe   tty7                          Fri Jul 26 17:58   still logged in   
 reboot   system boot  3.5.0-37-generic Fri Jul 26 17:57 - 20:10 (1+02:13)  

johndoe@computer::~$ last -f /var/log/wtmp
 reboot   system boot  3.5.0-37-generic Fri Jul 26 17:57 - 20:16 (1+02:19)   
 johndoe   pts/2        :0               Fri Jul 26 17:52 - 17:55  (00:03)    
 johndoe   pts/5        :0               Fri Jul 26 12:00 - 17:55  (05:55)    
 johndoe   pts/0        :0.0             Fri Jul 26 07:11 - 11:58  (04:46)
 <snip>...

有关详细信息，请参阅：Linux 显示登录日期和时间 以及命令“last”的手册页。