1.top --查看进程
2.su --临时切换用户命令
[root@tomato2 ~]# sudo su gongxijun
[gongxijun@tomato2 root]$
3.whoami ---我是谁 查看自己目前的用身份
[gongxijun@tomato2 root]$ whoami
gongxijun
4.exit ---退出当前用户
[gongxijun@tomato2 root]$ exit
exit
[root@tomato2 ~]#
5.ifconfig ---查看用户的ip信息 mac,eth0 ,ip 等等信息
[gongxijun@tomato2 root]$ ifconfig
eth0 Link encap:Ethernet HWaddr D0:50:99:17:37:1F
inet addr:192.168.0.155 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::d250:99ff:fe17:371f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1529804 errors:0 dropped:0 overruns:0 frame:0
TX packets:1549053 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:369566501 (352.4 MiB) TX bytes:1376257841 (1.2 GiB)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:31 errors:0 dropped:0 overruns:0 frame:0
TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2130 (2.0 KiB) TX bytes:2130 (2.0 KiB)

6.which --搜索命令(用于查找相关命令的位置)
[gongxijun@tomato2 root]$ which cat
/bin/cat
如果想要验证：

[gongxijun@tomato2 root]$ dir /bin/
alsaunmute dnsdomainname lsblk rview
arch domainname lscgroup sed
awk dumpkeys lssubsys setfont
basename echo mail setserial
bash ed mailx sh
cat egrep mkdir sleep
cgclassify env mknod sort
cgcreate ex mktemp stty
cgdelete false more su
cgexec fgrep mount sync
cgget find mountpoint tar
cgset findmnt mv taskset
cgsnapshot gawk nano tcsh
chgrp gettext netstat touch
chmod grep nice tracepath
chown gtar nisdomainname tracepath6
cp gunzip ping traceroute
cpio gzip ping6 traceroute6
csh hostname plymouth true
cut ipcalc ps umount
dash iptables-xml pwd uname
date iptables-xml-1.4.7 raw unicode_start
dbus-cleanup-sockets kbd_mode readlink unicode_stop
dbus-daemon keyctl red unlink
dbus-monitor kill redhat_lsb_init usleep
dbus-send link rm vi
dbus-uuidgen ln rmdir view
dd loadkeys rnano ypdomainname
df login rpm zcat
dmesg ls rvi

7.locate ---文件搜索命令

查找一个 iptables的文件 ，然后就可以搜索出这么多文件。
[gongxijun@tomato2 root]$ locate iptables
/bin/iptables-xml
/bin/iptables-xml-1.4.7
/etc/alternatives/bin-iptables-xml.x86_64
/etc/alternatives/iptables.x86_64
/etc/alternatives/man-iptables-restore.x86_64
/etc/alternatives/man-iptables-save.x86_64
/etc/alternatives/man-iptables-xml.x86_64
/etc/alternatives/man-iptables.x86_64
/etc/alternatives/sbin-iptables-multi.x86_64
/etc/alternatives/sbin-iptables-restore.x86_64
/etc/alternatives/sbin-iptables-save.x86_64
/etc/rc.d/init.d/iptables
在使用locate查找文件是，也可以使用星号表示所有字符，点号表示所有单字符。

举列子： 要查找所有以字母ca开头的文档

[gongxijun@tomato2 root]$ locate *a

/var/lib/yum/yumdb/z/b8019061884a679c3b9b867b44c7b9c64182240d-zip-3.0-1.el6-

x86_64/checksum_data
/var/log/sa
/var/log/samba
[gongxijun@tomato2
8. 手动更新数据库 --- updatedb
9. whereis ----特殊文件搜索命令
[gongxijun@tomato2 root]$ whereis cat
cat: /bin/cat /usr/share/man/man1/cat.1.gz /usr/share/man/man1p/cat.1p.gz
10. apropos --- 关键字搜索命令
[gongxijun@tomato2 root]$ apropos process