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[root@oracle ~]# tzselect
Please identify a location so that time zone rules can be set correctly.
Please select a continent or ocean.
1) Africa
2) Americas
3) Antarctica
4) Arctic Ocean
5) Asia
6) Atlantic Ocean
7) Australia
8) Europe
9) Indian Ocean
10) Pacific Ocean
11) none - I want to specify the time zone using the Posix TZ format.
#? 5
Please select a country.
1) Afghanistan 18) Israel 35) Palestine
2) Armenia 19) Japan 36) Philippines
3) Azerbaijan 20) Jordan 37) Qatar
4) Bahrain 21) Kazakhstan 38) Russia
5) Bangladesh 22) Korea (North) 39) Saudi Arabia
6) Bhutan 23) Korea (South) 40) Singapore
7) Brunei 24) Kuwait 41) Sri Lanka
8) Cambodia 25) Kyrgyzstan 42) Syria
9) China 26) Laos 43) Taiwan
10) Cyprus 27) Lebanon 44) Tajikistan
11) East Timor 28) Macau 45) Thailand
12) Georgia 29) Malaysia 46) Turkmenistan
13) Hong Kong 30) Mongolia 47) United Arab Emirates
14) India 31) Myanmar (Burma) 48) Uzbekistan
15) Indonesia 32) Nepal 49) Vietnam
16) Iran 33) Oman 50) Yemen
17) Iraq 34) Pakistan
#? 9
Please select one of the following time zone regions.
1) east China - Beijing, Guangdong, Shanghai, etc.
2) Heilongjiang (except Mohe), Jilin
3) central China - Sichuan, Yunnan, Guangxi, Shaanxi, Guizhou, etc.
4) most of Tibet & Xinjiang
5) west Tibet & Xinjiang
#? 1

The following information has been given:

China
east China - Beijing, Guangdong, Shanghai, etc.

Therefore TZ='Asia/Shanghai' will be used.
Local time is now: Wed Nov 28 10:24:46 CST 2012.
Universal Time is now: Wed Nov 28 02:24:46 UTC 2012.
Is the above information OK?
1) Yes
2) No
#? 1

You can make this change permanent for yourself by appending the line
TZ='Asia/Shanghai'; export TZ
to the file '.profile' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you
can use the /usr/bin/tzselect command in shell scripts:
Asia/Shanghai
[root@oracle ~]#

查看系统登录成功记录
#last
查看最后两笔登录记录
#last -n 2
查看指定用户的登录记录
#last oracle
oracle pts/0 :0.0 Thu Nov 22 08:53 still logged in
oracle pts/1 :0.0 Tue Nov 20 17:39 still logged in
oracle tty1 :0 Tue Nov 20 17:26 still logged in

清空登录日志文件（特殊编码）
[root@localhost root]# echo “”>/var/log/wtmp

再次查看系统登录记录
[root@localhost root]# last

查看系统登录失败记录
#lastb
root ssh:notty 192.168.1.50 Tue Nov 27 20:21 – 20:21 (00:00)
root ssh:notty 192.168.1.50 Tue Nov 27 20:20 – 20:20 (00:00)
root ssh:notty 192.168.1.50 Mon Nov 26 11:09 – 11:09 (00:00)
root ssh:notty 192.168.1.50 Tue Nov 20 17:11 – 17:11 (00:00)

清空登录系统失败记录（特殊编码）
# echo “”> /var/log/btmp
再次查看系统登录失败记录
# lastb

清空历史命令记录
[root@localhost root]# history -c

[root@localhost root]# echo “”> .bash_history

查看指定数量的最近命令记录
[root@oracle ~]# history 3
10 history
11 cat .bash_history
12 history 3
使用命令记录编号重复执行命令
[root@oracle ~]# !11
cat .bash_history
执行最后一次以tar起始的命令
[root@oracle ~]# tar xzf awstats-7.0.tar.gz
[root@oracle ~]# rm -rf awstats-7.0
[root@oracle ~]# !tar
tar xzf awstats-7.0.tar.gz
[root@oracle ~]#

历史命令记录数量控制
#env |grep HISTSIZE
HISTSIZE=1000

使用pwgen批量生成随机密码

安装

[root@oracle pwgen-2.06]# ./configure --prefix=/usr/local/pwgen
[root@oracle pwgen-2.06]# make
[root@oracle pwgen-2.06]# make install
mkdir -p /usr/local/pwgen/bin /usr/local/pwgen/man/man1
/usr/bin/install -c pwgen /usr/local/pwgen/bin/pwgen
/usr/bin/install -c -m 644 ./pwgen.1 /usr/local/pwgen/man/man1/pwgen.1
[root@oracle pwgen-2.06]#

查看帮助

[root@oracle bin]# ./pwgen --help
Usage: pwgen [ OPTIONS ] [ pw_length ] [ num_pw ]
Options supported by pwgen:
 -c or --capitalize
 Include at least one capital letter in the password
 -A or --no-capitalize
 Don't include capital letters in the password
 -n or --numerals
 Include at least one number in the password
 -0 or --no-numerals
 Don't include numbers in the password
 -y or --symbols
 Include at least one special symbol in the password
 -s or --secure
 Generate completely random passwords
 -B or --ambiguous
 Don't include ambiguous characters in the password
 -h or --help
 Print a help message
 -H or --sha1=path/to/file[#seed]
 Use sha1 hash of given file as a (not so) random generator
 -C
 Print the generated passwords in columns
 -1
 Don't print the generated passwords in columns
 -v or --no-vowels
 Do not use any vowels so as to avoid accidental nasty words

生成4组12位长度密码

[root@oracle bin]# ./pwgen 12 4
aik3ieC8oNee Chee6ririsi5 noiPo6aiquoo AeShaeriequ9

生成含有符号的4组12位长度密码

[root@oracle bin]# ./pwgen -y 12 4
uu!qu2Oobii4 kohM/ai6eith miReipi;th4e chu5ooj~ooNg

生成完全随机且含有符号的4组12位长度密码

[root@oracle bin]# ./pwgen -sy 12 4
g=~6J]!$}4Ws GK&0YCvj(pq~ AV`Q[Y|3wdwi ;0KUJ:f8bCCT

相关下载：
(1) pwgen 2.06

如果丢失 admin 密码，则可以使用下列步骤将安全设备重置到其缺省设置。配置 将失去，但是对设备的访问将恢复。要执行此操作，需要连接控制台。

注意: 在缺省情况下，会启用设备恢复功能。可通过输入 unset admin device-reset 命 令禁用它。同样，如果安全设备处于 FIPS 模式，恢复特征被自动禁用。

1. 在登录提示下，输入设备的序列号。

2. 在密码提示下，再次输入序列号。

出现以下消息:

!!!! Lost Password Reset !!!!You have initiated a command to reset the device to 
factory defaults, clearing all current configuration, keys and settings.Would 
you like to continue? y/n

3. 按 y 键。

出现以下消息:

!! Reconfirm Lost Password Reset !!If you continue, the entire configuration of 
the device will be erased.In addition, a permanent counter will be incremented 
to signify that this device has been reset.This is your last chance to cancel 
this command.If you proceed, the device will return to factory default 
configuration, which is: System IP: 192.168.1.1; username: netscreen; 
password: netscreen.Would you like to continue? y/n

4. 按 y 键，重置设备。现在可以用 netscreen 作为缺省用户名和密码进行登录。