转自:http://www.cnblogs.com/zhangdsh/archive/2011/08/03/2126694.html

新安装的CentOS5.5系统，在secureCRT下使用rz sz 上传下载文件时出现如下提示：

[root@webslave2 etc]# sz hosts
-bash: sz: command not found
[root@webslave2 etc]#

由上述现象可知，很可能没有安装相应的软件包；sz rz 命令所需要的软件包是lrzsz

下面检查软件包是否安装？

[root@webslave2 etc]# yum list installed lrzsz
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* addons: mirror.neu.edu.cn
* base: mirror.neu.edu.cn
* extras: mirror.neu.edu.cn
* updates: mirror.neu.edu.cn
Error: No matching Packages to list 由此可知没有安装此包
[root@webslave2 etc]#
下面安装lrzsz软件包，可通过yum安装，比较方便！

先查看下载源中的软件包

[root@webslave2 etc]# yum search lrzsz
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* addons: mirror.neu.edu.cn
* base: mirror.neu.edu.cn
* extras: mirror.neu.edu.cn
* updates: mirror.neu.edu.cn

===================== Matched: lrzsz ==========================
lrzsz.x86_64 : The lrz and lsz modem communications programs.

安装软件包（使用yum自动安装：）
[root@webslave2 etc]# yum -y install lrzsz
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* addons: mirror.neu.edu.cn
* base: mirror.neu.edu.cn
* extras: mirror.neu.edu.cn
* updates: mirror.neu.edu.cn
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package lrzsz.x86_64 0:0.12.20-22.1 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

=======================================================================
Package Arch Version Repository Size

======================================================================
Installing:
lrzsz x86_64 0.12.20-22.1 base 88 k

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

Total download size: 88 k
Downloading Packages:
lrzsz-0.12.20-22.1.x86_64.rpm | 88 kB 00:00
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : lrzsz 1/1

Installed:
lrzsz.x86_64 0:0.12.20-22.1

Complete!