| a | |
| alias | Create’s alias’s |
| apt-get | Package Manager for distro’s such as Ubuntu or debian based |
| aspell | Spell Checking tool |
| arp | Address Resolution Protocol, used to translate ip’s to hardware interface addresses |
| awk | Find and Replace text, database sort/validate/index |
| b | |
| bash | Bourne-Again SHell |
| bc | Arbitrary precision calculator language |
| bg | Launch in background |
| break | Quit a loop |
| builtin | Shell builtin |
| bzip2 | Compression / De-compression tool |
| c | |
| cal | Calendar |
| case | Conditionally performs a specified command |
| cat | Used to echo the contents of a file |
| cd | Change Directory |
| cfdisk | Partition table manipulator |
| chgrp | Change group owner |
| chmod | Change permissions |
| chown | Change file owner |
| chpasswd | Change user passwords in batch |
| chroot | Starts a command under a different root directory |
| chkconfig | Edit the system services |
| cksum | Display a CRC checksum and byte counts |
| clear | Clear screen |
| cmp | Compare files |
| comm | Compare two sorted files line by line |
| command | Run a command – ignoring shell functions |
| continue | Resume next iteration in a loop |
| cp | Copies files |
| cron | The Cron-daemon runs scheduled commands |
| crontab | Scheduler from the cron-daemon |
| csplit | Split a file into context-determined pieces |
| cut | Cuts files into several pieces |
| cupsd | Common UNIX Printing System, Starts the print scheduler Daemon. |
| d | |
| date | Display or edit date and time |
| dc | Calculator |
| dd | Writes boot records, disk headers and converts and copies files |
| ddrescue | Data recovery tool |
| declare | Declare variables and assign attributes |
| depmod | Create a dependency file for modules given on the command line |
| df | Display free disk space |
| diff | Differentiate between two files |
| diff3 | Differentiate between three files |
| dig | Performs DNS lookup (such as nslookup) |
| dir | List directory contents |
| dircolors | Assigns color setup for the ls command |
| dirname | Converts a pathname to a path |
| dirs | Display list of remembered directories |
| dmesg | Print kernel & driver messages |
| dpkg | Debian Package Manager. A packaging system for software distribution and installation |
| du | Estimate file usage on disk |
| e | |
| e2fsck | Checks and repairs a disk, specifically designed for ext2 and ext3 |
| echo | Displays a message on screen |
| egrep | Search files for lines that match an extended expression |
| eject | Eject Cd-tray |
| enable | Enable and disable builtin shell commands |
| env | Environment variables |
| ethtool | Ethernet card settings |
| eval | Evaluate several commands/arguments |
| exec | Executes commands |
| exit | Exit the shell |
| expect | Automate arbitrary applications accessed over a terminal |
| expand | Convert tabs to spaces |
| export | Sets an environment variable |
| expr | Evaluate expressions |
| f | |
| false | Do nothing, unsuccessfully |
| fdformat | Low-level format a floppy disk |
| fdisk | Partition table manager |
| fg | Send task to foreground |
| fgrep | Search file(s) for lines that match a fixed string |
| file | Determine file type |
| find | Search for files |
| finger | Display data about one or more users |
| fmt | Reformat paragraph text |
| fold | Wrap text to fit a specified width. |
| for | Expand words, and execute commands |
| format | Format utility |
| free | Displays memory usage |
| fsck | File system consistency check and repair |
| ftp | File Transfer Protocol |
| function | Define Function Macros |
| fuser | Identify/kill the process that is accessing a file |
| g | |
| gawk | Find and Replace text within files |
| getopts | Parse positional parameters |
| gcc | GNU Compiler Collection, compiles source files |
| grep | Search files for lines that match a given pattern |
| groups | Print group names where a user is listed |
| gzip | Compression / De-compression tool |
| h | |
| halt | Explicitly turns off the computer |
| hash | Remember the full pathname of a name argument |
| head | Output the first part of files |
| history | Command History |
| host | Print information about hosts or zones in DNS |
| hostname | Set or display the system hostname |
| i | |
| id | Print user and group id’s |
| if | Conditionally perform a command |
| ifconfig | Display network settings or configure a network interface |
| ifdown | Shutdown a network interface |
| ifup | Starts a network interface |
| import | Capture an X screen and save image |
| init | Initialize system. Usually executed from the boot loader |
| insmod | Loads a module into the kernel |
| install | Copy files and set attributes |
| iptables | Linux firewall,based on acls also does prerouting, natting, forwarding |
| j | |
| join | Join lines on a common field |
| k | |
| kill | Terminate a process from running |
| killall | Terminate processes by name |
| kudzu | Detects new and changed hardware by comparing against a db , Found on Redhat flavors |
| l | |
| less | Display output one screen at a time |
| let | Perform arithmetic on shell variables |
| ln | Create links between files (Shortcuts) |
| local | Create variables |
| locate | Find indexed files, Use updatedb to update index |
| logname | Print current login name |
| logout | Exit a login shell |
| look | Display lines beginning with a given string |
| lpc | Line printer control program |
| lpr | Offline print |
| lprint | Print a file |
| lprintd | Terminate print job |
| lprintq | Display print queue |
| lprm | Remove jobs from the print queue |
| ls | Show directory contents and file info |
| lsof | List open files |
| lspci | Lists all PCI devices, useful for debugging device drivers issues |
| lsmod | List all loaded kernel modules |
| lsusb | List all Universal Serial Bus (USB) devices, useful for debugging device drivers issues |
| m | |
| make | Compiles applications from source |
| man | Help manual |
| mkfs.ext3 | Create a journaling ext3 filesystem |
| mk2fs | Format device as a ext2 Filesystem |
| mkdir | Create new directory |
| mkfifo | Make FIFOs named pipes |
| mkisofs | Create ISO9660/JOLIET/HFS filesystem |
| mknod | Create block or character special files |
| more | Show output one screen at a time |
| mount | Mount a file system / device |
| mtools | Manipulate MS-DOS files |
| mv | Move or rename files or directories |
| mmv | Mass Move and rename (files) |
| n | |
| named | Internet domain nameserver daemon, usually the Bind ns |
| netstat | Displays Networking information |
| nice | Set the priority of a command or task |
| nl | Number lines and write files |
| nohup | Run a command immune to hangups |
| nslookup | Query’s dns information |
| nsupdate | Interactively submit dynamic DNS update requests to a nameserver |
| o | |
| open | Open a file in its default application |
| op | Operator access |
| p | |
| passwd | Change a users password |
| paste | Merge lines of files |
| pathchk | Check file name portability |
| perl | A powerful text-processing language utilizes many useful features of shell programs |
| ping | Uses ICMP to Test network connectiity |
| pkill | Terminate processes |
| popd | Restore the previous value of the current directory |
| pr | Prepare files for printing |
| printcap | Printer capability database |
| printenv | Print environment variables |
| printf | Format and print data |
| ps | Process status |
| pushd | Save and then change the current directory |
| pwd | Print Working Directory |
| python | A powerful object-oriented scripting language, many of the config scripts in Red Hat are driven by python |
| q | |
| quota | Display disk usage and limits |
| quotacheck | Utility for checking and repairing quota files |
| quotactl | Set disk quotas |
| r | |
| ram | ram disk device |
| rcp | Copy files between two different computers |
| read | read a line from standard input |
| readonly | Mark variables/functions as readonly |
| reboot | Restart the machine |
| renice | Alter priority of running processes |
| remsync | Synchronize remote files via email |
| return | Exit a shell function |
| rev | Reverse lines of a file |
| rm | Remove files |
| rmdir | Remove Directories |
| rpm | Red Hat Package Manager. A packaging system for software distribution and installation |
| rsync | Remote file copy/Synchronize |
| s | |
| screen | Multiplex terminal, run remote shells via ssh |
| scp | Secure copy (Uses ssh to copy files remotely) |
| sdiff | Merge two files interactively |
| sed | Stream Editor |
| select | Accept keyboard input |
| seq | Print numeric sequences |
| set | Manipulate shell variables and functions |
| sftp | Secure File Transfer Program (Uses Ssh) |
| shift | Shift positional parameters |
| shopt | Shell Options |
| shutdown | Shutdown or restart machine |
| sleep | Delay for a specified time, before executing another command |
| slocate | Find files |
| sort | Sort text files |
| source | Run commands from a file `.’ |
| split | Splits files into fixed-size parts |
| ssh | Secure Shell client (Such as putty on windows) |
| strace | Trace system calls and signals |
| su | Substitute user identity |
| sudo | Execute a command as a root user |
| sum | Display checksum for a file |
| symlink | Creates a symbolic link to a file |
| sync | Synchronize data on disk with memory |
| t | |
| tail | Output the last few lines of a file |
| tar | Saves many files together into a single tape or disk archive |
| tee | Redirect output to multiple files |
| test | Test a conditional expression |
| tftp | Trivial File Transfer Protocol, allows users to transfer files to and from a remote machine |
| time | Display how long a program ran for |
| times | User and system times |
| touch | Change file timestamps |
| top | List processes running on the system |
| traceroute | Display Route to Host via number of hops |
| trap | Run a command when a signal is set |
| tr | Translate, squeeze, and/or delete characters |
| true | Do nothing, successfully |
| tsort | Topological sort |
| tty | Print filename of terminal on std in |
| tune2fs | Tune the parameters of a ext2 partition by adjusting various parameters |
| type | Describe a command |
| u | |
| ulimit | Limit user resources |
| umask | Users file creation mask |
| umount | Unmount a device or partition |
| unalias | Stop an alias |
| uname | Print system information, such as kernel version etc |
| unexpand | Convert spaces to tabs |
| uniq | Uniquify files |
| units | Convert units from one scale to another |
| unset | Remove variable or function names |
| unshar | Unpack shell archive scripts |
| until | Execute commands (until error) |
| uptime | Prints current time, how long the system has been running, number of users currently logged in and system load averages |
| useradd | Create new user account |
| usermod | Modify user account |
| users | List users currently logged in |
| uuencode | Encode a binary file |
| uudecode | Decode a file created by uuencode |
| v | |
| vdir | Verbosely list directory contents (`ls -l -b’) |
| vi | The powerfull vi Text Editor |
| vim | An enhanced version of the vi editor |
| vmstat | Virtual mem statistics |
| w | |
| watch | Execute/display a program periodically |
| wc | Print byte, word, and line counts |
| whereis | Report all known instances of a command |
| which | Locate a program file in the user’s path. |
| while | Execute commands |
| who | Print all usernames currently logged in |
| whoami | Print the current user id and name (`id -un’) |
| whois | Search a whois database for a domain name, IP address, or NIC name |
| wget | Retrieve web pages or files from a location such as the internet |
| write | Send a message to another user |
| xy# | |
| xargs | Execute utility, passing constructed argument list(s) |
| yes | Print a string until interrupted |
| yum | Yellowdog Updater, Modified is an open-source package-management utility for RPM-compatible distros |
| . | Run a command script in the current shell |