Command not found的解决办法

如果在Linux运维中，遇到command not found的错误提示，

多半是由于缺乏相关软件包导致的，可以使用rpm安装的方法将相关软件安上。

以缺乏yum软件包为例：

[root@shijingnan ~]# mkdir /mnt/cdrom
mkdir: cannot create directory `/mnt/cdrom': File exists
[root@shijingnan ~]# mount -o loop /dev/cdrom /mnt/cdrom
mount: according to mtab /dev/sr0 is already mounted on /mnt/cdrom as loop
[root@shijingnan ~]# cd /mnt/cdrom
[root@shijingnan cdrom]# ls
AP    GPL       media.repo  RPM-GPG-KEY-redhat-beta-2
EFI   images    Packages    RPM-GPG-KEY-redhat-release-2
EULA  isolinux  repodata    TRANS.TBL
[root@shijingnan cdrom]# rpm -qa | grep yum
[root@shijingnan cdrom]# ll|grep yum
[root@shijingnan cdrom]# cd Packages
[root@shijingnan Packages]# ll|grep yum
-r--r--r--. 151 root root     12772 Mar 27  2010 anaconda-yum-plugins-1.0-5.1.el6.noarch.rpm
-r--r--r--.  72 root root    151272 Mar 27  2010 PackageKit-yum-0.5.6-2.el6.i686.rpm
-r--r--r--.  72 root root     87872 Mar 27  2010 PackageKit-yum-plugin-0.5.6-2.el6.i686.rpm
-r--r--r--. 220 root root    818788 Mar 27  2010 yum-3.2.25-12.el6.noarch.rpm
-r--r--r--.  72 root root     26812 Mar 27  2010 yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
-r--r--r--. 218 root root     13944 Mar 27  2010 yum-plugin-aliases-1.1.24-4.el6.noarch.rpm
-r--r--r--. 220 root root     17200 Mar 27  2010 yum-plugin-changelog-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root      9364 Mar 27  2010 yum-plugin-downloadonly-1.1.24-4.el6.noarch.rpm
-r--r--r--. 220 root root     10496 Mar 27  2010 yum-plugin-protect-packages-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root     24356 Mar 27  2010 yum-plugin-security-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root     13620 Mar 27  2010 yum-plugin-tmprepo-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root     18704 Mar 27  2010 yum-plugin-verify-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root     15788 Mar 27  2010 yum-plugin-versionlock-1.1.24-4.el6.noarch.rpm
-r--r--r--. 218 root root     32220 Mar 27  2010 yum-presto-0.6.2-1.el6.noarch.rpm
-r--r--r--. 218 root root     69696 Mar 26  2010 yum-rhn-plugin-0.9.1-2.el6.noarch.rpm
-r--r--r--. 218 root root     75804 Mar 27  2010 yum-utils-1.1.24-4.el6.noarch.rpm
[root@shijingnan Packages]# rpm -ivh yum-3.2.25-12.el6.noarch.rpm
warning: yum-3.2.25-12.el6.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID f21541eb: NOKEY
error: Failed dependencies:
        yum-metadata-parser >= 1.1.0 is needed by yum-3.2.25-12.el6.noarch
[root@shijingnan Packages]# ll | grep yum-metadata
-r--r--r--.  72 root root     26812 Mar 27  2010 yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
[root@shijingnan Packages]# rpm -ivh yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
warning: yum-metadata-parser-1.1.2-14.1.el6.i686.rpm: Header V3 RSA/SHA256 Signature, key ID f21541eb: NOKEY
Preparing...                ########################################### [100%]
   1:yum-metadata-parser    ########################################### [100%]
[root@shijingnan Packages]# rpm -ivh yum-3.2.25-12.el6.noarch.rpm
warning: yum-3.2.25-12.el6.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID f21541eb: NOKEY
Preparing...                ########################################### [100%]
   1:yum                    ########################################### [100%]
[root@shijingnan Packages]# yum repolist
local                                                                                  | 3.7 kB     00:00 ... 
repo id                                              repo name                                          status
local                                                local                                              2,865
repolist: 2,865
[root@shijingnan Packages]# yum install tree
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package tree.i686 0:1.5.3-1.el6 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================
 Package                Arch                   Version                          Repository               Size
==============================================================================================================
Installing:
 tree                   i686                   1.5.3-1.el6                      local                    36 k

Transaction Summary
==============================================================================================================
Install       1 Package(s)
Upgrade       0 Package(s)

Total download size: 36 k
Installed size: 63 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
rhn-check-0.9.3-2.el6.noarch has missing requires of yum-rhn-plugin >= ('0', '0.5.3', '30')
  Installing     : tree-1.5.3-1.el6.i686                                                                  1/1 

Installed:
  tree.i686 0:1.5.3-1.el6                                                                                     

Complete!