First, the date and time
DATE : Displays the current time
% Y ----------------------- years
% M ----------------------- month
% D ----------------------- Day
% H ----------------------- time
% M ----------------------- points
% S ------------------------ seconds
-s ------------------------ set the system time
CAL : Calendar
cal Year ------------------------- show a calendar year
Second, task scheduling
The timing of the implementation of pre-existing script
crontab
Edit crontab -e -------------------- regular tasks
crontab -l --------------------- interleaved regular tasks
crontab -r --------------------- delete a scheduled task
Execute a script:
Month and week does not appear at the same time
Third, disk partitions and mount
lsblk -f ------------------ view decency partitions and mount case
Steps: 1, adding a hard disk SATA
2, the partition: fdisk / dev / sdb ---------- m --- n --- p --- --- W ---- generated all the way round sdb1
3, Format: mkfs -t ext4 / dev / sdb1
4, mount: mount / dev / sdb1 / mnt (cancel is umount / mnt)
5, permanent mount: vim / etc / fstab ------- modified as
Fourth, the disk consumption inquiry
df -h -------------------- view the current disk usage
du : Statistical instruction
a ------------------ file statistics
c ------------------ Summary
s ------------------ catalog statistics
h ------------------ added with units of measurement
WC : statistical instructions
l -------------- statistical line
w ------------ Counting words
c ------------- statistical character
1, the query how many files under a directory: LS the -l / path | grep "^ -" | wc -l
2, query the number of directories under a directory: LS the -l / path | grep "^ d" | wc -l
3, at a directory inquiries number of files and subfolders: LS -lR / path | grep "^ -" | wc -l
4, query the number of directories and subdirectories under a directory: LS -lR / path | grep "^ d" | wc -l