UNIX = system designed at Bell Labs, created by Dennis Ritchie
Linux = derivative of UNIX, created by Linus Torvalds
Dennis Ritchie = creator of UNIX, C programming language, hero to us all
Linus Torvalds = chief designer of Linux, creator of Git version control
Richard Stallman = advocate of GNU Linux, founder of FSF, creator of Emacs
Bjarne Stroustrup = the creator of the C++ language
Be prepared to read a lot. A manpage is basically an instruction book on how to use a certain command. If you need more info about some commands, just man the command.
- man - read the manpage of a given command (man cat)
- which - print the path of an executable (which gcc -> /usr/bin/gcc)
- ls - list files (ls /home)
- cd - choose directory (cd /home)
- cat - output the contents of a file (cat hello.txt)
- touch - touch a file to modify it's timestamp (and make it exist) (touch hello.txt)
- nano - open up a text editor to modify a given file (nano hello.txt)
- pwd - print your current working directory (pwd -> /home/myname/somedir)
- less - read the contents of a file in a friendly scrollable manner
- more - opposite of more
- find - find a file amongst a given directory
- rm - remove a file or directory
- cal - print out a calendar
- date - print out current date/time (lots of options)
- echo - print something out to standard input
- wc - count the lines, chars and words of a file
- read - read a line of standard input
- tee - copy a line of input to given files
- grep - filter lines based on a given pattern
- sed - transform and manipulate text streams
- awk - similar to sed, but more programming-like
- sh - the standard "shell" environment program, executes shell files
- bash - the Bourne Again Shell (BASh), basically sh++, default shell for all Linuxes
- expr - evaluate basic arithmetic expressions (expr 2+2 -> 4)
- gcc - the GNU C Compiler, compiles a C program file to a binary
- g++ - the GNU C++ Compiler, same as gcc but does C++ programs
- ssh - create a secure connection to a host (ssh me@google.com)
- python - friendliest language out there, learn it
- git - tool for version control database
- sleep - take a nap for N seconds, zzz....
- alias - bind commands to names to avoid repeating yourself
- make - very common build system utility to build projects using Makefiles
- vi, vim - programmer's choice text editor
- emacs - Richard Stallman's choice text editor
- sqlite - barebones SQL database program, can read SQL files and manipulate them
- chmod - change the "mode" of a file
- chown - change the owner of a file
- useradd, usermod, userdel - take a guess
- groupadd, groupmod, groupdel - take another guess
- users - prints users logged into host
- groups - prints groups you belong to
- passwd - changes your password on the system (please remember it if you change it)
- tar - the most default archiving utility on Linux
- zip - bare-bones compression, compresses multiple files/dirs into one "zip" file
- gzip, gunzip, zcat - much better compression algorithm
- ping - send an ICMP packet repeatedly to an address and return info
- wget - fetch a resource at a specified destination (wget google.com)
- wifi - toggle wifi-hardware on your device
- ifconfig - manipulate your network devices
- iptables - mess with this and soon your internet will go out
- traceroute - trace a packet route to a target host (try traceroute 4.2.2.2)
- nmap - networking Swiss Army Knife - scan open ports, see MAC IDs, etc
- sudo - elevate yourself to Admin-level privileges
- su - run command with a different user ID, or log into root shell
- ps - lists processes running (ps aux will list all procs running)
- dmesg - see kernel-level messages (try using "less dmesg")
- gdb - low-level debugger for any program
- strace - see OS calls made by a program
- bg, fg - run jobs in backgrounds or bring them to the foreground
- kill - kill a process by it's PID
- killall - kill all procs with the given name (killall firefox)
- top - monitor the status of all running programs
- htop - a much better to look at 'top'
- env - a user-created "environment" of custom variables
- write - write messages to other users