首先查看安装的软件包，或者时候安装有某某软件包的命令

rpm  （-qa）| grep 软件名

root@mode oldboy]# rpm -qa| grep openssl

openssl-devel-0.9.8e-22.el5

openssl-0.9.8e-22.el5

openssl-0.9.8e-22.el5

openssl-devel-0.9.8e-22.el5

[root@mode oldboy]# yum search openssl

Loaded plugins: fastestmirror, security

Loading mirror speeds from cached hostfile

file:///mnt/cdrom/repodata/repomd.xml: [Errno 5] OSError: [Errno 2] No such file or directory: '/mnt/cdrom/repodata/repomd.xml'

Trying other mirror.

=============================== Matched: openssl ===============================

m2crypto.x86_64 : Support for using OpenSSL in python scripts

openssl.i686 : The OpenSSL toolkit

openssl.x86_64 : The OpenSSL toolkit

openssl-devel.i386 : Files for development of applications which will use

                   : OpenSSL

openssl-devel.x86_64 : Files for development of applications which will use

                     : OpenSSL

openssl-perl.x86_64 : Perl scripts provided with OpenSSL

openssl097a.i386 : The OpenSSL toolkit

openssl097a.x86_64 : The OpenSSL toolkit

perl-Crypt-SSLeay.x86_64 : Crypt::SSLeay - OpenSSL glue that provides LWP https

                         : support

perl-Net-SSLeay.x86_64 : Perl extension for using OpenSSL

pyOpenSSL.x86_64 : Python wrapper module around the OpenSSL library

xmlsec1.i386 : Library providing support for "XML Signature" and "XML

             : Encryption" standards

xmlsec1.x86_64 : Library providing support for "XML Signature" and "XML

               : Encryption" standards

xmlsec1-openssl.i386 : OpenSSL crypto plugin for XML Security Library

xmlsec1-openssl.x86_64 : OpenSSL crypto plugin for XML Security Library

xmlsec1-openssl-devel.i386 : OpenSSL crypto plugin for XML Security Library

xmlsec1-openssl-devel.x86_64 : OpenSSL crypto plugin for XML Security Librar

假设在生产环境中，系统的关键文件/etc/inittab被删除了（系统还没重新启动。崩溃前），不要急。以下告诉你该怎样处理。

1、模拟误删除文件

[root@localhost ~]# rm -rf /etc/inittab

[root@localhost ~]# cat /etc/inittab

cat: /etc/inittab: No such file or directory

2、新建该文件，并查看相应包的相关信息

[root@localhost ~]# touch /etc/inittab

[root@localhost ~]# rpm -qf /etc/inittab

initscripts-8.45.19.EL-1

3、确定了包的相关信息，挂载安装光盘，进行查找

[root@localhost ~]# cd /mnt/yum/

[root@localhost yum]# ll

total 0

[root@localhost yum]# cd ~

[root@localhost ~]# mount /dev/cdrom /mnt/yum

mount: block device /dev/cdrom is write-protected, mounting read-only

[root@localhost ~]# cd /mnt/yum/Server/

[root@localhost Server]# cp initscripts-8.45.30-2.el5.i386.rpm /tmp

cp: overwrite `/tmp/initscripts-8.45.30-2.el5.i386.rpm'? y

[root@localhost Server]# cd /tmp

[root@localhost tmp]# ll

total 1680

drwx------ 2 root root    4096 Feb 17 13:45 bin

drwx------ 9 root root    4096 Feb 17 13:45 etc

drwx------ 3 root root    4096 Feb 17 13:53 gconfd-root

-r--r--r-- 1 root root 1651907 Feb 17 15:41 initscripts-8.45.30-2.el5.i386.rpm

drwx------ 2 root root    4096 Feb 17 13:53 keyring-06YG9F

drwx------ 2 root root    4096 Sep 26 08:44 keyring-elqVM1

drwx------ 2 root root    4096 Sep 26 08:08 keyring-jTNbTb

drwx------ 3 root root    4096 Feb 17 13:45 lib

srwxr-xr-x 1 root root       0 Feb 17 13:54 mapping-root

drwx------ 2 root root    4096 Feb 17 15:38 orbit-root

drwx------ 2 root root    4096 Feb 17 13:45 sbin

drwx------ 2 root root    4096 Feb 17 13:53 ssh-ROxTuK6949

drwx------ 4 root root    4096 Feb 17 13:45 usr

drwx------ 4 root root    4096 Feb 17 13:45 var

drwx------ 2 root root    4096 Feb 17 13:54 virtual-root.2eelUV

drwxrwxrwt 2 root root    4096 Feb  5 12:19 VMwareDnD

drwx------ 2 root root    4096 Feb 17 13:53 vmware-root

4、解压包的信息

[root@localhost tmp]# rpm2cpio initscripts-8.45.30-2.el5.i386.rpm |cpio -imd

10748 blocks

[root@localhost tmp]# ll

total 1680

drwx------ 2 root root    4096 Feb 17 13:45 bin

drwx------ 9 root root    4096 Feb 17 13:45 etc

drwx------ 3 root root    4096 Feb 17 13:53 gconfd-root

-r--r--r-- 1 root root 1651907 Feb 17 15:41 initscripts-8.45.30-2.el5.i386.rpm

drwx------ 2 root root    4096 Feb 17 13:53 keyring-06YG9F

drwx------ 2 root root    4096 Sep 26 08:44 keyring-elqVM1

drwx------ 2 root root    4096 Sep 26 08:08 keyring-jTNbTb

drwx------ 3 root root    4096 Feb 17 13:45 lib

srwxr-xr-x 1 root root       0 Feb 17 13:54 mapping-root

drwx------ 2 root root    4096 Feb 17 15:38 orbit-root

drwx------ 2 root root    4096 Feb 17 13:45 sbin

drwx------ 2 root root    4096 Feb 17 13:53 ssh-ROxTuK6949

drwx------ 4 root root    4096 Feb 17 13:45 usr

drwx------ 4 root root    4096 Feb 17 13:45 var

drwx------ 2 root root    4096 Feb 17 13:54 virtual-root.2eelUV

drwxrwxrwt 2 root root    4096 Feb  5 12:19 VMwareDnD

drwx------ 2 root root    4096 Feb 17 13:53 vmware-root

5、进行文件替换与简单改动

[root@localhost tmp]# cp ./etc/inittab /etc/

cp: overwrite `/etc/inittab'? y

[root@localhost tmp]# cat /etc/inittab

收工！！！！

！

。！

yum search 软件名

rpm -qf 软件名