Linux: for more information on many of the below commands/functions, see the respective man pages ----- edit cron jobs: sudo crontab -e view cron jobs: sudo crontab -l md5sum --> generate hash of a file vimtutor --> learn vim basics host --> lookup website's IP address debug in bash with -x and -xv which shell am I using? echo $SHELL which desktop environment am I using? echo $XDG_CURRENT_DESKTOP or use screenfetch / neofetch remove newlines from a file: tr -d '\n' < file.txt vim will let you look through AND EDIT the contents! work with word lists and regexes: find all three-letter words with no vowels: egrep -i "^[^aeiouy']{3}$" /usr/share/dict/words find all four-letter words that begin with p and end with l: look p | egrep ^p..l$ file: determine file type change shell (to bash, in this case): chsh -s /bin/bash sudo apt-get {update, dist-upgrade} update will resync package index files upgrade will install the newest versions of all packages & dist-upgrade will handle changing dependecies as well as do upgrade lsb_release -a will print distribution-specific information search for R packages: // see http://cran.r-project.org/bin/linux/debian/ apt-cache search ^r-.* install R: sudo apt-get install r-base screen: http://www.rackaid.com/blog/linux-screen-tutorial-and-how-to/ screen help CTRL + A, then ? new screen CTRL + A, then c switch between screens CTRL + A, then n or p detach CTRL + A, then d re-attach screen -r create a running log of the session CTRL + A, then H lock your screen CTRL + A, then x list running processes ps aufx remove html tags from text stream: sed 's/<[^>]\+>//g' See what shell you are running: ps -p $$ print out some system info (CPU speed and temperature): MHZ=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq) TEMPE=$(cat /sys/class/thermal/thermal_zone0/temp) echo CPU Speed $(($MHZ/1000)) Mhz "|" CPU Temp $(($TEMPE/1000)) C DNS resolver information: /etc/resolv.conf User information: /etc/passwd Run command on login and/or make aliases for commands: ~/.bashrc (or .profile) ex: alias ll='ls -l' Change a user's home directory: usermod -d /path/to/new/homedir/ username Generate a public/private key pair: ssh-keygen -t dsa Replace a String in Multiple Files in Linux Using Grep and Sed: grep -rl matchstring somedir/ | xargs sed -i 's/string1/string2/g' dpkg --get-selections // list installed packages dpkg-query -l // also works; see https://wiki.debian.org/ListInstalledPackages xkill = kill a program in linux In Ubuntu, press Alt-F2 and then enter the following command: xkill top = view running processes in linux man = help ctrl + alt + f1 = switch to full-screen terminal ctrl + alt + f7 = switch back to GUI install a .deb package: sudo dpkg -i packagename.deb remove a .deb package: sudo dpkg -r packagename df -h // This will output the usage of each partition in the server. df -h --total // this will also output the TOTAL memory usage du -sh /home/ // list the size of a specific directory du -sh /home/* //list all the subdirectory sizes under /home du --max-depth=1 -h / <-- this will show how much space folders are taking up, without recursing and printing out for each subfolder # This will enter a full screen terminal called tty1: ctl+alt+f1 # Then find the program you wanna kill: (ps -e lists them!) ps -e | grep programname # Then when you find the program name kill it: killall programname # Then go back to your display manager using terminal: ctl+alt+f7 GParted and PartedMagic: http://distrowatch.com/weekly.php?issue=20070806 upload files to Dropbox using the Dropbox-Uploader script, available at https://github.com/andreafabrizi/Dropbox-Uploader need to authorize root to use it, as well as any user(s), especially if you want to use it in a cronjob Reset Windows password: 1. get chntpw -- run (sudo dpkg -i chntpw*) in a folder containing a .deb package 2. Mount Windows partition/harddrive 3. cd to /media/ and then to /WINDOWS/system32/config/ 4. change admin password with (sudo chntpw SAM) change user password with (sudo chntpw -u SAM) USERS ----- add a user useradd USER passwd USER mkdir /home/USER chown USER /home/USER // change user su - username // verify it worked: whoami add user to sudoers: sudo adduser paul sudo modify sudoers file via visudo username ALL=(ALL) ALL make the user not have to enter password to run sudo with: username ALL=(ALL:ALL) NOPASSWD:ALL need .bashrc and ~/.profile change hostname: vi /etc/hostname then run: hostname NEW_HOSTNAME then run: hostname (to verify) also change it via vi /etc/hosts change user's home directory: // also see vi /etc/default/useradd usermod -m -d /home/USER USER change user's shell: usermod -s /bin/bash USER alternatively, run: sudo chsh -s /bin/bash // else change it in /etc/passwd change user login usermod -l login-name old-name view user information: id, finger setting up Apache ----------------- if a2ensite doesn't work for enabling sites-available, rename the file to *.conf 5 Deadly Linux Commands You Should Never Run, from http://www.maketecheasier.com/deadly-linux-commands/ (accessed 10/22/2014) -------------------------------------------- Delete everything recursively: rm -rf / Fork bomb: :(){ :|: & };: Move contents of home folder to /dev/null: mv ~ /dev/null Format hard drive: mkfs.ext3 /dev/sda Output command to hard drive: any-command > /dev/sda Windows and/or Linux -------------------- objdump -Dslx file tracert, tracepath, and/or traceroute = tool in Windows/Linux for tracing the route taken to an IP address/URL IRC --- register a nick: /msg NickServ register PASSWORD EMAIL_ADDRESS only allow 30 seconds for password: /msg NickServ SET ENFORCE ON Nick yournick is temporarily unavailable: /msg NickServ RELEASE yournick yourpassword get info about a channel: /msg ChanServ info ##channelname register a channel: /msg ChanServ register ##channelname make yourself an operator of a channel: /msg ChanServ op #channel yournick get VERSION/client that someone is using (don't do too often!): /ctcp VERSION weechat ------- enable channel list in left sidebar: /script install buffers.pl have it mark you as away and display a message about screen when you detach: /script install screen_away.py run shell commands within IRC: /script install shell.py /shell -o will pipe to IRC /shell will not irssi ----- close a window: /WINDOW CLOSE git --- change remote URL: git remote set-url origin git://new.url.here Windows ------- nslookup --> lookup website's IP address God Mode: Folder called GodMode.{ED7BA470-8E54-465E-825C-99712043E01C} net statistics server / net stats srv --> get uptime msconfig --> enable/disable startup programs regedit --> edit the registry resmon --> Resource Monitor (something like a more detailed Task Manager) tasklist taskkill (more info: http://forums.techarena.in/tips-tweaks/1161770.htm) diskpart - list disk - select disk 2 - clean right click on My Computer and click "Manage" - Disk partition management Windows + L = lock computer Excel: Alt+Enter = new line Excel: drop down menus: Data>>Validation>>Settings Excel: Array formulas (Control+Shift+Enter) source: http://office.microsoft.com/en-us/excel-help/introducing-array-formulas-in-excel-HA001087290.aspx Sysinternals tools: http://live.sysinternals.com/ or \\live.sysinternals.com\tools\ Process Idle Tasks (and potentially speed up your computer): http://buzzblogging.com/tweaks/how-to-clean-up-your-windows-xp-memory/ Start>>Run (or Windows Key + R) (or even from cmd) %windir%\system32\rundll32.exe advapi32.dll,ProcessIdleTasks remove items from right-click context menus: regedit: HKEY_CLASSES_ROOT\*\shellex\ ContextMenuHandlers HKEY_CLASSES_ROOT\Directory\shellex\contextmenuhandlers Add "Open Command Window in this Folder" to right-click context menu on folders: Manual Method: (This requires editing your registry. If you are not familiar with registry editing, this isn't for you, so skip to the easy method below) 1. Open regedit 2. Navigate to HKEY_LOCAL_MACHINE/Software/Classes/Folder/Shell 3. Create a new key called Command Prompt 4. Your default value should be Command Prompt Here 5. Create a new key called Command under the Command Prompt key 6. Your default value should be cmd.exe /k pushd %L Your popup menu when you right click on a folder will now contain an option called Command Prompt Here which will open a command prompt in the selected folder. Source: http://www.tech-recipes.com/rx/232/right-click-to-open-a-command-prompt/ move windows (useful if they are stuck off screen): Alt+Space R = Restore Alt+Space X = Maximize Alt+Space M = Move (can use arrow keys) source: http://www.howtogeek.com/howto/windows/bring-misplaced-off-screen-windows-back-to-your-desktop-keyboard-trick/ Full screen cmd.exe in XP: Alt+Enter source: http://www.windowsnetworking.com/articles_tutorials/windows-xp-keyboard-shortcuts.html device manager: mmc devmgmt.msc Javascript ---------- Wayback Machine bookmarklet (archive this! button): javascript:window.location="http://web.archive.org/web/*/"+window.location; Harlem Shake in browser; works well on Wikipedia: javascript:(function(){function c(){var e=document.createElement("link");e.setAttribute("type","text/css");e.setAttribute("rel","stylesheet");e.setAttribute("href",f);e.setAttribute("class",l);document.body.appendChild(e)}function h(){var e=document.getElementsByClassName(l);for(var t=0;te&&s.heightt&&s.width=w&&t<=b+w}function S(){var e=document.createElement("audio");e.setAttribute("class",l);e.src=i;e.loop=false;e.addEventListener("canplay",function(){setTimeout(function(){x(k)},500);setTimeout(function(){N();p();for(var e=0;eIf you are reading this, it is because your browser does not support the audio element. 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