內存查看命令：free
自定義命令：alias
[root@localhost ~]# free total used free shared buffers cached Mem: 8302800 7965944 336856 0 47184 5046216 -/+ buffers/cache: 2872544 5430256 Swap: 5668856 208 5668648
Linux總內存量：total, 可用內存：free+buffers+cached，已用內存 total-(free+buffers+cached)
爲了方便查看內存使用率，自定義命令如下
[root@localhost ~]# alias lsfree="free|awk '{print \$2,\$3,\$4,\$6,\$7}'|sed -n '2p'|awk '{print \"total:\"\$1/1024\"MB\",\"free:\"(\$3+\$4+\$5)/1024\"MB\",\"proportion:\"(\$3+\$4+\$5)/\$1*100\"%\"}'"改爲永久生效：切換至目錄(centos) ~/.bashrc, 添加以上命令，保存，立即生效：source ~/.bashrc
[root@localhost ~]# more .bashrc
# .bashrc
# User specific aliases and functions
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
alias lsfree="free|awk '{print \$2,\$3,\$4,\$6,\$7}'|sed -n '2
p'|awk '{print \"total:\"\$1/1024\"MB\",\"free:\"(\$3+\$4+\$5)
/1024\"MB\",\"proportion:\"(\$3+\$4+\$5)/\$1*100\"%\"}'"
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
[root@localhost ~]# lsfree
total:8108.2MB free:5297.31MB proportion:65.3327%