通過yum安裝iftop
直接用命令安裝：
yum install -y iftop
如果安裝的時候報下面這種錯：
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.nju.edu.cn
* extras: mirrors.nju.edu.cn
* updates: mirrors.nju.edu.cn
No package iftop available.
Error: Nothing to do
就需要改一下yum源：
vim /etc/yum.repos.d/epel.repo
把下面這段粘進去
[epel]
name=Extra Packages for Enterprise Linux 7 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch
metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 7 - $basearch - Debug
#baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch/debug
metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 7 - $basearch - Source
#baseurl=http://download.fedoraproject.org/pub/epel/7/SRPMS
metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=1
然後執行：
cd /etc/pki/rpm-gpg
wget https://archive.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7
最後再次執行
yum install -y iftop
iftop安裝完成。
debian安裝iftop
apt-get install iftop -y