sort lines of text files
read from standard input and write to standard output and files
Control the systemd system and service manager
Yellowdog Updater Modified
remove files or directories
RPM Package Manager
print lines matching a pattern
read Info documents
an interface to the on-line reference manuals
归档数据
make directories
list directory contents
list contents of directories in a tree-like format
concatenate files and print on the standard output
copy files and directories
display a line of text
change file mode bits
change file timestamps
make block or character special files
print system information
Control the system hostname
Display amount of free and used memory in the system
delay for a specified amount of time
get locale-specific information
initialize a terminal or query terminfo database
change and print terminal line settings
print or set the system date and time
report a snapshot of the current processes.
Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
masquerade: 伪装 multicast: 多播
updates and queries runlevel information for system services
search for files in a directory hierarchy
build and execute command lines from standard input
terminate a process
run a command immune to hangups, with output to a non-tty
create a new group
modify a user account
log in to a new group
administer /etc/group and /etc/gshadow
print the groups a user is in
print real and effective user and group IDs
transfer data between file descriptors
rename files
make link between files
display Linux processes
print resolved symbolic links or canonical file names
report file system disk space usage
estimate file space usage
convert and copy a file
ext2/ext3/ext4 file system debugger
file perusal filter for crt viewing
opposite of more
determine file type
check file types and compare values