Common Linux commands can be used to query instances of a single command

Common Linux commands

Common command formats in Linux:

command [option] [argument1] [argument2] ... Where option starts with "-", multiple options can be connected with one "-", for example, "ls-l-A" and "ls-La" have the same effect. Parameters are optional or required according to different commands. All commands accept input from standard input, and the output results are displayed in standard output, while the error information is displayed in standard error output devices. You can use the redirection function to redirect these devices. The command returns a zero value after a normal execution result. If an error in the command is not completely completed, a non-zero value is returned (a variable is available in Shell $? View ). This return value can be used in shell scripts as part of the control logic.

HELP command:

Man obtains help information about related commands. For example, man dir can obtain usage information about dir. For example, info can obtain detailed information about how to use info.

File Operations:

Cat display file content and Merge multiple files clear screen chattr change file properties chgrp change file group right chmod change file or directory permissions chown change File Ownership comm compare two sorted the file CP copies the file to another file. dd reads data from the specified file and writes the data to the specified file. df reports disk space usage. Diff compares two text files, list the disk space occupied by the du statistics directory/file in different rows File identification file type Emacs Powerful editing Environment Find search file and perform the specified operation (find2) grep searches for file content in the given mode. Head: displays the first few rows of the specified file. Less: displays the file on the page. ln: Creates a file link. Locate: searches for eligible files. More: displays the text file MV by frame on the terminal screen. move or rename a file or directory RM/rmdir delete file/directory sed use script to process text files sort specified files by row tail display the last part of the specified file touch Create File tr convert the character VI full-screen editor WC to display the number of lines in the specified file, number of words or characters which searches for files that meet the conditions in the environment variable $ path

Compression and backup:

Bzip2/bunzip2. bz2 File compression/decompression program cpio backup file dump backup file system gzip/gunzip. GZ File compression/decompression program gzexe compression Executable File restore Restore files backed up by dumping (dump) operations or the entire file system (a partition) TAR archives or reads unarj files and decompress them. ARJ file zip/unzip compression/decompressed ZIP file zipinfo list details of zip files

Disk operation:

CD/pwd switch directory/display current working directory DF display disk information du display directory or file size e2fsck check ext2/ext3 File System correctness fdisk partition fsck check file system and try to fix errors losetup setup loop device ls list directory content mkdir create directory mformat format disk for MS-DOS File System Format mkbootdisk create current system boot disk mke2fs create ext2 File System mkisofs make ISO Disc image File Mount/umount mount file system/unmount file system quota displays the space used by the disk and restrictions sync writes data in the memory buffer into the disk tree to list the contents of the directory in a tree

System Operation:

Alias sets command alias chkconfig check, set the system service clock to adjust the RTC time date display or set the system time and date dmesg to display the boot information eval re-calculate the parameter content exit current shellexport settings or display the environment variable finger search and Display User information free Display memory status hostid show host ID hostname show host name ID show user identity kill Delete executing program or work last list current and past logged on to system user information logout exit system lsmod display loaded system module modprobe automatic processing load module passwd Set User Password PS process Status Report Program Status reboot Restart computer rhwo view system user rlogin remote login RPM manage Linux kits Program shutdown su switch user change user identity top display, manage the execution program uname Display System Information useradd/userdel Add User/delete user userinfo graphical interface modify tool usermod modify user attributes, including the User Shell Type, user group, etc, you can even change the logon name W to display the currently registered user and the user's running command whereis to determine the binary Execution Code of a command, source code and help location who lists users using the system whois to find and Display User Information

Network Communication:

ARP Address display and control FTP file transmission lftp file transmission Mail Send/receive email mesg allow or deny other users to send information to their own terminal mutt e-mail management program ncftp File transmission netstat displays network connection, route table, and network interface information. Pine sends and receives emails, browse newsgroup Ping send ICMP echo request packet to the host on the network remote logon Telnet in SSH safe mode remote logon talk conversation with another user traceroute show the path to reach a host and the time used by wget to automatically download the file write from the network to write information to other users' terminals.