man: Manual means the manual, you can use this command to query the use of other commands
pwd: Print working directory passwords mean
su: Switch user to switch the user to root
cd: Change directory Change directory
ls: List files list the files in the directory
ps: Process Status Process Status
mkdir: Make directory to create the directory
rmdir: Remove directory Mobile Directory
cat: Concatenate series
uname: Unix name system name
df: Disk free spare hard disk
du: Disk usage hard disk usage
mv: Move file Move files
rm: Remove file deleted file
cp: Copy file to copy files
ln: Link files Link files
chmod: Change mode to change the mode
tar: Tape archive extracting file
sudo is short for superuser do