linux常用命令

cat /etc/issue
输出：
CentOS Linux release 7.6.1810 (Core)

which mysql

df -h
输出：
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   27G  1.3G   26G   5% /
devtmpfs                 7.8G     0  7.8G   0% /dev
tmpfs                    7.8G     0  7.8G   0% /dev/shm
tmpfs                    7.8G   18M  7.8G   1% /run
tmpfs                    7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/vda1               1014M  175M  840M  18% /boot
/dev/vdb1                200G   33M  200G   1% /mnt/app
tmpfs                    1.6G     0  1.6G   0% /run/user/0