wget 安装：Package wget-1.14-18.el7_6.1.x86_64 already installed and latest version

  wget 命令是 Linux 系统中最常用的指定链接文件下载命令，wget 稳定性很好，即使服务器带宽很小，不稳定，该命令也很实用。如果服务器存在网络不稳定现象导致文件下载失败，wget 会自动尝试重新下载，直到文件下载完毕。如果因为本地带宽或服务器其他操作中断了下载，下次使用 wget 执行同链接下载，它会自动从中断的地方继续下载文件。

  wget 用法示例如下：

[root@iZuf6crxor2b7uwzq9sutyZ local]# wget http://download.redis.io/releases/redis-4.0.8.tar.gz-bash: wget: command not found

  上述命令报错：-bash: wget: command not found。原因是系统中没有安装 wget，我们只要执行安装命令安装即可。

  安装方法很简单，只需执行命令 “yum -y install wget”，即可完成安装。

[root@iZuf6crxor2b7uwzq9sutyZ local]# yum -y install wgetLoaded plugins: fastestmirrorDetermining fastest mirrors * centos-sclo-rh: mirrors.aliyun.com * centos-sclo-sclo: mirrors.aliyun.combase | 3.6 kB 00:00:00 centos-sclo-rh | 3.0 kB 00:00:00 centos-sclo-sclo | 3.0 kB 00:00:00 epel | 4.7 kB 00:00:00 extras | 2.9 kB 00:00:00 mysql-connectors-community | 2.6 kB 00:00:00 mysql-tools-community | 2.6 kB 00:00:00 mysql57-community | 2.6 kB 00:00:00 updates | 2.9 kB 00:00:00 (1/8): epel/x86_64/group_gz | 96 kB 00:00:00 (2/8): extras/7/x86_64/primary_db | 225 kB 00:00:00 (3/8): epel/x86_64/updateinfo | 1.0 MB 00:00:00 (4/8): epel/x86_64/primary_db | 6.9 MB 00:00:00 (5/8): updates/7/x86_64/primary_db | 5.7 MB 00:00:00 (6/8): mysql-connectors-community/x86_64/primary_db | 72 kB 00:00:00 (7/8): mysql-tools-community/x86_64/primary_db | 85 kB 00:00:00 (8/8): mysql57-community/x86_64/primary_db | 258 kB 00:00:00 Package wget-1.14-18.el7_6.1.x86_64 already installed and latest versionNothing to do

  上述安装命令结束时，提示：

Package wget-1.14-18.el7_6.1.x86_64 already installed and latest version Nothing to do

  说明 wget 已经存在，使用如下命令查找 wget 发现确实存在。

[root@iZuf6crxor2b7uwzq9sutyZ ~]# rpm -qa | grep "wget"wget-1.14-18.el7_6.1.x86_64

  wget 存在，但是使用时仍然提示 “-bash: wget: command not found”，解决方法：卸载 wget，再次安装。

  卸载命令：yum remove wget。

[root@iZuf6crxor2b7uwzq9sutyZ ~]# yum remove wgetLoaded plugins: fastestmirrorResolving Dependencies--> Running transaction check---> Package wget.x86_64 0:1.14-18.el7_6.1 will be erased--> Finished Dependency ResolutionDependencies Resolved======================================================================================================================================================================= Package Arch Version Repository Size=======================================================================================================================================================================Removing: wget x86_64 1.14-18.el7_6.1 @base 2.0 MTransaction Summary=======================================================================================================================================================================Remove 1 PackageInstalled size: 2.0 MIs this ok [y/N]: yDownloading packages:Running transaction checkRunning transaction testTransaction test succeededRunning transaction Erasing : wget-1.14-18.el7_6.1.x86_64 1/1 warning: file /usr/bin/wget: remove failed: No such file or directory Verifying : wget-1.14-18.el7_6.1.x86_64 1/1 Removed: wget.x86_64 0:1.14-18.el7_6.1 Complete!

  提示卸载成功。再次安装，命令如下。

[root@iZuf6crxor2b7uwzq9sutyZ ~]# yum -y install wgetLoaded plugins: fastestmirrorLoading mirror speeds from cached hostfile * centos-sclo-rh: mirrors.aliyun.com * centos-sclo-sclo: mirrors.aliyun.comResolving Dependencies--> Running transaction check---> Package wget.x86_64 0:1.14-18.el7_6.1 will be installed--> Finished Dependency ResolutionDependencies Resolved======================================================================================================================================================================= Package Arch Version Repository Size=======================================================================================================================================================================Installing: wget x86_64 1.14-18.el7_6.1 base 547 kTransaction Summary=======================================================================================================================================================================Install 1 PackageTotal download size: 547 kInstalled size: 2.0 MDownloading packages:wget-1.14-18.el7_6.1.x86_64.rpm | 547 kB 00:00:00 Running transaction checkRunning transaction testTransaction test succeededRunning transaction Installing : wget-1.14-18.el7_6.1.x86_64 1/1 Verifying : wget-1.14-18.el7_6.1.x86_64 1/1 Installed: wget.x86_64 0:1.14-18.el7_6.1 Complete!

  提示安装成功，此时再次使用 wget 下载 redis tar 包，即可完成下载。

[root@iZuf6crxor2b7uwzq9sutyZ ~]# wget http://download.redis.io/releases/redis-4.0.8.tar.gz--2021-03-17 11:22:45-- http://download.redis.io/releases/redis-4.0.8.tar.gzResolving download.redis.io (download.redis.io)... 45.60.125.1Connecting to download.redis.io (download.redis.io)|45.60.125.1|:80... connected.HTTP request sent, awaiting response... 200 OKLength: 1729973 (1.6M) [application/octet-stream]Saving to: ‘redis-4.0.8.tar.gz’100%[=============================================================================================================================>] 1,729,973 4.30MB/s in 0.4s 2021-03-17 11:22:46 (4.30 MB/s) - ‘redis-4.0.8.tar.gz’ saved [1729973/1729973]