eject Ejects removable media such as CD's, DVD's, Zip lpr [­P] Print textfile on the line reset Resets the terminal to a normal state. Often needed drives. printer. Make sure it is a textfile­­don't print after catting a binary file. env Run a command in a modified environment. machine­code files! (See reset.) rev Reverses lines from file. exec Execute command from a new shell. lprm [­P] Remove job from printer rm Remove (delete) a file from the disk. expand Converts tabs to spaces. queue. rmdir

Removes directory dir. expr Evaluate expressions. ls [­a][l] List the files in the current directory on the sed Stream editor. Lots of options for modifying files file Determines the type of the file. screen. Without the ­a option, filenames starting passing through sed. find Find files by almost any criterion with “.” will not be listed. ­l option generates a sh Launches Bourne shell. except by their contents. “long” listing with file permissions, sizes, shutdown Shuts system down, or at least pretends finger Displays information about users. timestamps, etc. to. Sends shutdown notice to all logged­in users. free Displays amount of free and allocated memory in the lsmod Lists driver modules loaded into Linux kernel. shutdown ­h now Shuts system down to a true halt, system. lspci Lists devices connected to the PCI bus. immediately. funzip Used for unzipping files in a pipeline. man [] Print the online sleep delays processing for n seconds. fsck File system check. A front end to utilities to check manual entry for the Unix command on the sort Sorts file contents. various filesystems, e.g., ext2, ext3, ext4, reiserfs, screen. The manual entry is piped through split ­b size Splits a file into smaller files of size bytes. vfat, etc. more, so use , , and q (etc.) as strings Filters out all except ASCII strings from a g++ [­g] [­o ] [...] described for more. file. Compile C++ source file, file.cpp. File mesg [y|n] Permits or denies writing to your console. stty Set terminal options. name must end with ``.cpp'' or “.c”. Machine code mkdir Create a new directory. su Request superuser privileges in a new shell. object file will be a.out unless ­o option is used. ­g mkfs Front end to utilities which build a filesystem on sux su with X­windows passthrough. option embeds debugging data for gdbg or kdbg. a formatted disk. (Note that Unix distinguishes su Become a different user in a new shell. grep file Search file for string(s) matching the between formatting, i.e., creating the pattern of swapon Starts use of indicated swap space. regexp. tracks and sectors, and making a filesystem on swapoff Terminates use of indicated swap space. group Lists the groups to which the user belongs. that pattern.) sync Synchronize filesystems. (Update disk filesystem grub­install Installs the Grand Unified Bootloader. mkswap Prepares a partition to be used as swap (i.e., data from memory's filesystem data. Use sync gzip, gunzip Used to compress and decompress files. virtual memory) space. before pulling a removable read­write filesystem Zip does not compress as effectively as Bzip2. modprobe Adds driver modules to or removes such as a floppy or USB flash drive. head [­c bytes|­n lines] Filters out all but the modules from a running kernel. tail [­c bytes|­n lines] Filters out all but the last (tail) top (head) lines or bytes of file. more Print textfile on the screen, one characters or lines of a file. hostname Prints domain name or IP address. screenful at a time. gives one more tar Use to create and manage file archives. id [] Prints real and effective UID's and GID's screenful. gives one more lineful. less tar xvfz De­zip (z option) archive and extract (x for logged in user or user. is more powerful; more is aliased to less on option) all files from archive file file.tgz. info Displays manual information bout GNU many systems. tar xvfj Same as "tar xvfz" except file.tbz is a commands. mount ­t bzip2­compressed archive. insmod Installs driver module into running kernel. Use Mounts a filesystem. One of and tee Copies standard input to standard output and to a modprobe instead; it's more flexible. is optional if both are listed in file. ispell Interactive spell­checking /etc/fstab. touch Updates a file's timestamp. Creates an kill Terminate the process with the indicated process ID mv Move file1 to path­and­filename file2. empty file if none exists. number. Commonly used to rename files. tty Reports what device or terminal you are using. last Display listing of last logged­in users. nano Launch text editor from pine email client. Not umask Masks out permissions. E.g., less Same as more, but has additional commands: b found on all Unix systems, since nano is not umask 77 prevents group and others from being moves back one screenful. Experiment to see what free software. given access to new files by default. other keys do. Press q (quit) when done. nl Prints file with line numbers. umount | Unmounts filesystem. ln [­s] Creates file2 as a [symbolic] link printf Prints formatted output. uname Gives operating system name and version. to file1. ps List processes running on the computer. ps aux uniq Removes duplicate lines. locate Searches for files on the local system. lists all processes. uncompress Uncompresses compressed files. lpq [­P] Print a listing of the jobs on a printer pwd Print current working directory on screen. vi Edit file using vi editor. If file doesn't exist, it will be queue. read ... Reads value of var1, var2, created. See vi reference card for vi commands. … from the keyboard. w Prints statistics on logged­in users and their system utilization. wc [­c|­w|­l] Count characters, words, or lines in a file. Unix Job Control, I/O Redirection and Multiple Unix Commands whereis Find path to a command. Commands Michael P. Conlon, Ph.D. which Displays the full pathname of a command. Execute command in foreground. who Prints statistics on logged­in users. & Execute command in background, i.e., Slippery Rock University whoami Prints your usercode. return the prompt without waiting for the August 26, 2010 write Sends a message to another logged­in user. command to complete. Often used when launching GUI programs from the command apropos List Unix commands whose descriptions in Network Commands shell. the online manual contain the string. Used for finding finger [@] Find user information. D End of text. Used to indicate end­of­file for unknown commands. ftp Download/upload files using FTP protocol. keyboard input and to log out of single­user apt­get Utility to install (etc.) software packages in Debian Insecure. Use for anonymous FTP only. mode. Linux and derivatives, e.g., Ubuntu. host DNS or reverse DNS lookup. C Kill foreground job. (Doesn't always work.) at ­f file Execute commands from file at the hostname Find domain name or IP address of your Z Suspend the running job. indicated time. computer. fg Resume the suspended job in the foreground. awk A pattern matching program. Good for separating ifconfig Set/get network interface parameters. bg Resume the suspended job in the background. out parts of files. ifdown Brings network interface down. nohup & Executes command in basename Strips all but the filename from the given ifup Brings network interface up. Usually background. Command is not killed by logging path. is eth0 for ethernet, ppp0 for dialup. out. bash Start a new bash shell. Invokes dhcpcd if necessary. > Send standard output from bzip2, bunzip2 Compress or uncompress files. Bzip does ipcalc Compute IP info for a host. the command into file. First delete file if it tighter compression than gzip does. lynx Text Web browser already exists. bzcat Displays a file compressed with bzip2. mail Send/receive email. Interactive mode is unfriendly. >> Append standard output cat Copy the file to stdin, normally the monitor. Used to send mail within scripts. from the command onto file. cd Change current working directory nc Netcat. Connects standard input to a TCP or UDP < Read from file rather than to directoryname. channel. from keyboard (standard input). chgrp Changes the group­ownership of nc Connects stdin to on using | Run command1 the file. TCP. and command2 concurrently. Use output from chmod [ugo][+|­][rwx] Change the permissions on file netstat Gives data and statistics about network connections, command 1 as input to command2. adding (deleting) read, write, and/or execute routing tables, interfaces, masquerading, etc. && Run command2 if permissions to user, group, others. Don't type the ping Determine whether is command1 completes successfully. brackets! reachable, and the communication delay. || Run command2 chown Sets user as the owner of file. ping6 Similar to ping, but for IP v6. only if command1 is unsuccessful. clear Clears the console screen. rlogin Remote login. Insecure. Do not use. compress Compresses files. Gzip and bzip2 route Set/get routing info. compress better. History sftp @ Download/upload files securely. cp Copy file1 to file2. Part of Secure Shell suite. history Lists previous commands and their numbers. cut Cuts characters or fields from standard input. ssh @ Secure remote login. !n Repeat command # n. date Query or set computer clock. ssh ­X @ Secure remote login, supporting ! Repeat the most recent command that started dc An arbitrary­precision "desk calculator" using remote X­Windows functionality. with str. reverse Polish notation. telnet Remote login. Insecure. Do not use. and can be used to scroll dd ­if= ­of= Copies from input file to output tracepath Traces the path to , through the history. file, byte­by­byte. Often used to clone disks or to and finds the path MTU. create disks from disk­image files. wget [option]... [URL] Download files from the 'net Filename Completion diff Lists differences between file1 and file2. using http or ftp. Can even download entire At any point in a command when typing a file name, dirname Strips all but the path from the given Websites, modifying links into local ones. pressing will complete the filename up to filename. zcat Displays a file compressed with gzip. an ambiguity. Type enough additional dmesg Display Unix bootstrap messages. characters to disambiguate, and press du Displays disk utilization statistics. again. echo Copy the string to the console.