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

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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

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如果在生产环境中，系统的重要文件/etc/inittab被删除了（系统还没重启，崩溃前），不要急，下面告诉你该如何处理。  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，并查看对应包的相关信息  [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修改  [root@localhost tmp]# cp ./etc/inittab /etc/  cp: overwrite `/etc/inittab'? y  [root@localhost tmp]# cat /etc/inittab  收工！！！！！！！

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