A collection of useful commands I've picked up over time (history | grep X). Understanding the purpose of each parameter is left to the reader - note typing '/' in man lets you search for specific terms in the manual page. Note that these commands have all been tested on an Ubuntu installation, and with the exception of package management they should work universally. Many commands require extra permissions and start with "sudo" - take extra caution when using these. I update this page pretty frequently. Always lots to learn! :)

Index of commands:

• aspell (command line spell checking)
• apt/dpkg (package management, software installation)
• cp/mv/rm (copy, move, delete files)
• dd (clone a hard drive, backup drive to file)
• df/du/find (drive usage)
• ffmpeg (video transcoding, desktop recording, etc.)
• gcc (creating software programs)
• git (revision control system)
• grep (search files for strings)
• locate (search for files/directories)
• man (software documentation)
• mount (enabling access to drives/filesystems)
• rsync (backups)
• ssh (log into another machine)
• tar/gzip (archive, compress)

• blacklisted nvidia_experimental_310 issue
• copy/pasting into the terminal
• filesystem mounting options for a solid state drive
• using udisks and gnome-session-properties to automount partitions on login
• changing file ownership on a USB drive not formatted to FAT32
• getting multi-monitor settings with nvidia-settings to stick after reboot
• removing overlay-scrollbar from default Ubuntu installation
• fixing the fontconfig warning when running applications
• setting up an environment for making documents with TeXworks and LaTeX
• switching between qt4 and qt5 with qtchooser
• open a terminal through nautilus
• youtube issues with chromium
• hostnames, avahi and .local
• linker errors using webkitwidgets
• convert a PDF into a series of images
• remove cached startup errors
• digitally sign a PDF
• s3cmd - Manage Amazon S3 buckets (webhosting)

• aspell (command line spell checking)

  Spell check an input file:

  aspell -c sample.tex Spell check an input file (do not create backup file): aspell -dont-backup -c sample.tex Show personal dictionary (note: the first one does not work on Ubuntu, alternate provided): aspell dump personal sudo updatedb locate .aspell* cat ~/.aspell.en.pws Show aspell configuration: aspell dump config

• apt/dpkg (package management, software installation)

  Add a package:

  sudo apt-get install package_name Remove a package: sudo apt-get remove package_name Add repository: sudo apt-add-repository ppa:sample_ppa/sample Search packages: sudo apt-get update apt-cache search search_term List installed packages: dpkg -l List files and directories of an installed package: dpkg -L package_name

• cp/mv/rm (copy, move, delete files)

  Copy a file:

  cp /example/file1 /example/file2 Copy a directory (dir1 into dir2): cp -a /example/dir1 /example/dir2 Move a file: mv /example/file1 /example/file2 Delete a file: rm /example/file1 Delete a directory (be careful): rm -rf /example/dir

• dd (clone a hard drive, backup drive to file)

  List drives and partitions:

  sudo fdisk -l Clone a drive (note: drive /dev/sdb must have size greater than or equal to /dev/sda): sudo dd if=/dev/sda of=/dev/sdb Clone drive to a file (note: output file location should not be on any partition of /dev/sda): sudo dd if=/dev/sda of=/home/sda_as_backup_file Report progress (sends signal to dd every 10 seconds): ps au | grep dd sudo watch -n 10 "kill -USR1 processid" List partition UUIDs: sudo blkid Modify partition UUID (if ext2/3/4, device is e.g. /dev/sda1): tune2fs -U random /dev/sda1

• df/du/find (drive usage)

  Report usage for all mounted drives:

  df -h Show sorted usage of directories at root: sudo du -hsx /* | sort -n List files bigger than 100 MB: find -size +100M -ls

• ffmpeg (video transcoding, desktop recording, etc.)

  Record desktop (at 24 fps, 1920x1080 resolution, on screen 0, using mpeg4):

  ffmpeg -f x11grab -y -r 24 -s 1920x1080 -i :0+0,0 -vcodec mpeg4 -sameq sample_out.mp4 Record desktop (400x400 portion of desktop at offset 200x200 on screen 1): ffmpeg -f x11grab -y -r 24 -s 400x400 -i :1+200,200 -vcodec mpeg4 -sameq sample_out.mp4 Record webcam/microphone: ffmpeg -f alsa -ac 2 -i hw:0 -i /dev/video0 -acodec ac3 -ab 128k -vcodec mpeg4 -sameq -r 24 sample_out.mp4 Transcode video (and resize): ffmpeg -i sample.mp4 -sameq -s hd720 sample_720.mp4 Transcode audio only: ffmpeg -i sample.mp4 -vcodec copy -acodec aac -sameq sample_out.mp4 Speed up video: ffmpeg -i sample.mp4 -vf "setpts=0.05*PTS" -r 25 -s hd720 -sameq sample_out.mp4 Rotate video 90 degrees clockwise: ffmpeg -i sample.mp4 -vf "transpose=1" -sameq sample_out.mp4 Rotate video 90 degrees counter-clockwise: ffmpeg -i sample.mp4 -vf "transpose=2" -sameq sample_out.mp4 Video overlay: ffmpeg -i sample.mp4 -aspect 4:3 -vf "movie=overlay.png [logo]; [in][logo] overlay=0:0:1" -sameq sample_out.mp4 Images to video: ffmpeg -r 1 -i dgplogo%01d_1080.png -sameq sample_out.mp4 Merge videos (not supported by all formats): ffmpeg -i "concat:sample1.avi|sample2.avi" -vcodec copy -acodec copy sample_out.mp4

• gcc (creating software programs)

  Compile object file(s):

  gcc -c sample.c -o sample.o Create static library (.a): ar crs libsample.a sample.o Create shared library (.so): gcc -shared -o libsample.so sample.o Linking a static library (creates executable program "test_static"): gcc -static test.c -L. -lsample -o test_static Linking a shared library (creates executable program "test_shared"): gcc test.c -L. -lsample -o test_shared Add shared library path: (General) Append path to /etc/ld.so.conf (Ubuntu) Append path to /etc/ld.so.conf.d/.conf Update shared library paths: sudo ldconfig Add shared library path temporarily to run executable: #!/bin/bash LD_LIBRARY_PATH=/directory/for/libs/:$LD_LIBRARY_PATH echo 'looking for shared libraries here first' $LD_LIBRARY_PATH /path/to/executable View shared libraries needed by executable, and paths to files linked at runtime: ldd /path/to/executable Output assembly code (extension is .s): gcc -S -c sample.c

• git (revision control system)

  Configure username and email (globally), and set merge tool: git config --global user.name "My Name" git config --global user.email "example@email.ca" git config merge.tool kdiff3 Copy remote repository contents locally: git clone https://github.com/Example/repo.git Add and show remote repository (call it "upstream"): git remote add upstream https://github.com/Example/repo.git git remote -v See history of repository ("upstream"): git log upstream Show details of last commit: git show Show remote branches (fetch updates local list): git fetch git branch -r Show local branches: git branch Delete local branch: git branch -D branch_name Add files to be committed: git add /path/to/files Upload all local changes to master branch of remote repository "origin": git commit -a -m'made some changes' git push origin master Merge pull request: git pull upstream master Stash local changes (to pull): git stash Merge another branch to active branch (note this auto-commits): git merge origin/some_branch Show merge conflicts: git status Resolve merge conflicts: git mergetool Revert all local changes to previous commit: git reset --hard commit_hash_value Create a new branch: git branch new_branch Switch to work on other branch: git checkout new_branch

• grep (search files for strings)

  Search file for string: grep search_string filename Output line numbers where search string is found: grep -n search_string filename Display filenames containing search string: grep -l search_string filenames*

• locate (search for files/directories)

  Search:

  locate 'search_term1 search_term2' Search (case insensitive): locate -i search_term Update filesystem database: sudo updatedb Find locations of program executable/source/documentation: whereis program_name Locate a command: which program_name

• man (software documentation)

  View manual page:

  man program_name
Search manual pages for keyword: man -k keyword apropos keyword

• mount (enabling access to drives/filesystems)

  List mounted drives:

  mount Mount a device (SATA drive 1, /media/drivedir must exist): sudo mkdir /media/drivedir sudo mount /dev/sda1 /media/drivedir Unmount device: sudo umount /media/drivedir

• rsync (backups)

  Back up a directory:

  rsync -av source_path dest_path Back up a directory and exclude files/directories: rsync -av --delete-excluded --ignore-errors --exclude=*.gvfs* --exclude='.local' source_path dest_path Creating a backup script: #!/bin/bash echo "Backing up..." # may want to mount drive for source/dest paths first here rsync -av source_path dest_path chmod 744 ./backup.sh Set ownership of dest path (e.g. if new partition owned by 'root'): chown james:james /media/james/Drive -R

• ssh (log into another machine)

  Connect to server using ssh:

  ssh username@server_address Create public/private key (RSA): ssh-keygen -t rsa List keys loaded: ssh-add -l Add a new key: ssh-add /path/to/private_key Print key fingerprint: ssh-keygen -lf /path/to/key

• tar/gzip (archive, compress)

  Create archive of directory and compress:

  tar -czvf file.tar.gz /path/to/compress/

  Extract archive:

  tar -xvf file.tar.gz

  Compress single file:

  gzip input_file

  Uncompress single file:

  gunzip input_file.gz

On getting nvidia_experimental_310 to work:

I had issues getting the nvidia_experimental_310 package working. It turned out there was a "nvidia_experimental_310" entry in a file "/etc/modprobe.d/blacklist-local.conf" causing the trouble. How and why that got there I may never know. Commands I tried to track down this problem and my path to a solution:

Show loaded modules (with 'nvidia' in name):

[ 10.865] (EE) NVIDIA: Failed to load the NVIDIA kernel module. Please check your
[ 10.865] (EE) NVIDIA: system's kernel log for additional error messages.
[ 10.865] (EE) Failed to load module "nvidia" (module-specific error, 0)

Show kernel log (and view in 'less'):

Show all nvidia kernel objects:

Existence of the kernel object for the current version of the kernel I'm running (uname -r) is encouraging as it means when installing the nvidia_experimental_310 package it compiled OK. Let's try to link it into the kernel again ourselves.

Load a module (in this case, 'nvidia_experimental_310'):

Blacklisted? Huh?

Search all blacklisted modules (whose name contains 'nvidia'):

Aha! After removing blacklist-local.conf which contained the above entry, I tried again.

Load a module, then restart display manager:

Working well!

copy/pasting into the terminal:

"Control-Shift-V" pastes text directly into the terminal, avoiding the need to right click and choose "Paste" each time.

filesystem mounting options for a solid state drive:

You can edit "fstab" (the file system table) by doing the following:

using udisks and gnome-session-properties to automount partitions on login:

changing file ownership on a USB drive not formatted to FAT32:

getting multi-monitor settings with nvidia-settings to stick after reboot:

removing overlay-scrollbar from default Ubuntu installation:

Fortunately, it is easy to disable the "overlay scrollbars". On Ubuntu 12.04:

fixing the fontconfig warning when running applications:

setting up an environment for making documents with TeXworks and LaTeX:

switching between qt4 and qt5 with qtchooser:

open a terminal through nautilus:

youtube issues with chromium:

hostnames, avahi and .local:

linker errors using webkitwidgets:

convert a PDF into a series of images:

remove cached startup errors:

digitally sign a PDF:

s3cmd - Manage Amazon S3 buckets (webhosting):