donovanglover-nix-config/help/commands.md

Common Commands

• Move files: mv <source> <dest>
• Move directories: mv -r <source> <dest>
• Copy files: cp <source> <dest>
• Copy directories: cp -r <source> <dest>
• Copy all files from one directory to an existing directory (includes dotfiles and subdirectories): cp -R dir_1/. dir_2/

Note that "renaming" files is the same as moving them from one location to another. For example, if you want to rename a file oldfile to newfile, then you would type mv oldfile newfile.

• Print the contents of a file: cat <filename>
• Batch rename multiple files: rename -v <find_this_string> <replace_with_this_string> <in_these_files>
• Remove (delete) files: rm <filename>
• Remove (delete) a directory: rm -r <dirname>
• Make a new file: touch <filename>
• Make a new directory: mkdir <dirname>
• List all the files in a directory: ls OR find
• List all the directories in a directory: ls -d */
• List all the files in a directory, including dotfiles: ls -A
• List all the files in dirname: ls <dirname>
• Only list png and jpg files: ls *.{png,jpg}
• Print the file type based on header information: file <filename>
• Show all running processes as a tree: pstree
• Print the number of new lines: wc -l <file>
• Print the maximum line length: wc -L <file>
• Print the word count: wc -w <file>
• Show the size of the current directory, including subdirectories: du -h
• Show the size of the current directory and its files: du -ha
• Get more information about any command: man <command>

Switching Directories

• Go up one directory: ..
• Go up two directories: ...
• Go to the home directory: ~ OR simply cd with no parameters
• Go to dirname: dirname

Note that for all of the above, cd is not required.

Other Commands

• Print the working directory: pwd
• Termite the processes with a specific word in it: killall -q <word>
• Get the current time and settings: timedatectl
• Show what gets executed when you run a command: which <command>
• Create a symbolic (soft) link between two files: ln -s <source> <dest>
  • When a program references dest, it will link to and give source.
  • In comparison, a hard link is when you make a copy of the file
• Give permissions to the user hello and the group world: chown -R hello:world dir/
• Given text input, return only unique lines (aka no duplicates): cat <input_file> | uniq
• Search for a particular font on the system: fc-list | grep -i <font>
• Search for all files of a specific extension in a given directory: find . -name "*.ext" -type f
  • Chain -delete to the end of the find command in order to delete the results
  • This is useful if, for example, you want to delete all files with the extension ext in all directories and subdirectories

Changing File Permissions

• Make a script executable: chmod +x <file>
• Change the permissions of a directory to all users: chmod -R a+rwX dir/
• Give anyone and everyone access to a directory: chmod -R 777 dir/
  • Useful for deleting files that the current user can't delete

Note that you should never give a file or directory more permissions than needed. a+rwX and 777 should only be used in extreme situations where you have to change permissions before using a file. You should change the permissions back or delete the file when you're done.

Searching Through Files

• Search all files in a directory (and all subdirectories) for a given string: grep -inr <search_term> OR g <search_term>
• Search all files in a directory (including subdirectories) for a given string and ignore dotfiles: ag <search_term>

System Commands

• Logout of the current user session: logout
• Restart the system: reboot
• Turn off the computer: poweroff

Installed Commands

These programs are installed on top of the base system.

• List the entire contents of a directory: tree
• List all the directories in a directory, up to 2 levels deep: tree -d -L 2
• Beautify any JSON output: <json_output> | jq '.'
• Easily search for a file in a directory and its subdirectories: fzf
• Show duplicate files in a given directory, with the ability to remove them as well: fdupes <dir>
  • Add -r to go through subdirectories
  • Add -n to exclude empty files
  • Add -f to omit the first file in each set of matches
  • Add -1 to list each set of matches on a single line
  • Add -S to show the size of each duplicate file
  • Add -d to delete duplicates during execution
  • Add -A to ignore hidden files

Inox

• Open a webpage in a borderless window: inox --app=<url>
• Open a webpage in the regular browser window: inox <url>

Waterfox

• Open a webpage in a new window: waterfox --new-window <url>
• Open a webpage in a new tab: waterfox --new-tab <url>
• Search for a specific term: waterfox --search <term>

Jekyll

• Start a server and monitor it for changes (useful for development): jekyll serve
• Start a server and detach it from the current shell: jekyll serve --detach
• Terminate a jekyll server that was detached from the shell: kill -9 <pid>
• Terminate all jekyll servers: pkill -f jekyll

Note that you can run multiple servers on different ports through Jekyll and other software.

Crystal

• Build and run the program directly: crystal <file>
• Compile the program to binary: crystal build <file>
  • Add --progress or -p to show build progress
  • Add --release when you're building the release version (takes longer)
  • Add --no-debug to increase the build speed (useful for dev builds)
  • Add -o to specify the location of the output file

LaTeX

• Make a pdf of your document: pdflatex <file>
  • Add -output-directory <dir> to specify the location for build files (.aux, .pdf, .log, etc.)
    • The directory <dir> must exist before you can write to it
  • Note that all pdflatex options must come before specifying <file>

Xclip

Using the X clipboard

• Copy the result of any command to the X clipboard: command | xclip
  • This is particularly useful for commands like fzf, where you want to search for a specific file then do something with it
• Paste the results from the X clipboard: xclip -o

Using the global clipboard

• Copy a file to the global clipboard: xclip -sel clip < filename.txt OR cat filename.txt | xclip -sel clip
  • Note that -sel is shorthand for -selection and that clip is shorthand for clipboard
• Copy the result of any command to the global clipboard: command | xclip -sel clip
• Paste the results from the global clipboard: xclip -o -sel clip

Secure Shell

• Make a new 4096-bit RSA key: ssh-keygen -t rsa -b 4096 [-C <comment>]
  • Note that id_rsa is your private key and id_rsa.pub is your public key
• Add your new key to SSH: ssh-add ~/.ssh/id_rssa
• Copy your public key: xclip -sel clip < ~/.ssh/id_rsa.pub
• Add a location to your known hosts: ssh -T <location>
  • For example, if you wanted to use SSH with GitHub, you would add the location git@gitlab.com
• Start the SSH agent: eval "$(ssh-agent -s)"

Note that a git repository must be cloned with SSH if you want to use SSH with it.

Dealing with Archives

• Zip all files in a directotry: zip -r <zip_name> <directory>
• View the contents of rar files: unrar lb <files>
• Extract the contents of rar files: unrar x <files>
• Extract the contents of zip files: unzip <files>
• Extract any type of archiving algorithm: extract <filename>

Note: When using unrar or unzip to extract multiple files (with wildcards), you must first escape the * to \*.

Opening Things

Note that the preferred way to open things is with the open function; however, sometimes it is necessary to use these commands if, for example, you're loading an entire directory.

• Open a video or multiple videos in a playlist: mpv <files/dir>
• Open an image or multiple images: feh <files/dir>
  • Add -r to recursively iterate through all subdirectories
  • Add -z to randomize the order of the images
  • Use -l to enable list mode, an easy way to see various details about images
  • Use -t to enable thumbnail mode, a quick and easy way to see all the images in a directory
    • Add -E <pixels> to set the thumbnail height
    • Add -y <pixels> to set the thumbnail width
    • Note that generating thumbnails takes time (i.e. don't use with large file sizes)

Firejail

Use firejail to sandbox a program or other piece of software. This ensures that the program does not have access to your entire file system since it runs in a restricted environment.

• Run a program in firejail with its default profile (if it exists): firejail <program>
• Use firejail by default for all programs that have profiles: firecfg
  • List all the programs that use firejail by default: firecfg --list
  • Remove all symbolic links to firejail: firecfg --clean
• Verify that firejail is being used for a particular program: firejail --list

Pacaur

Although the examples above use pacman, they apply for pacaur as well.

• Install packages: pacman -S <packages>
• Remove packages (including dependencies no longer needed): pacman -Rs <packages>
• Update all packages: pacman -Syu
• Search for a specific package: pacman -Ss <package>
• List all self-installed packages (i.e. from the AUR): pacman -Qm

Note that if you ever get 404s with pacman or pacaur, you need to update your local database to the new download locations with -Syu first.

Other Pacman Variants

• View the dependencies of a package in tree format: pactree -c <package>
  • Add -d 1 to limit the depth of the tree to one level deep
• List all the packages that depend on a certain package: pactree -rc <package>
• Remove all cached versions of packages except the most recent one: paccache -rk1
• Remove all cached versions of uninstalled packages: paccache -ruk0

Working with Online Resources

• Download anything online: wget <url>
• View the response header and contents of any webpage: http <url>

Custom Commands

• Easily switch to a 4k resolution with DPI scaling: 4k
• Easily switch to a 1080p resolution (with 96 DPI): 1080p
• Run a command as root: pls <command>
• Run the previous command as root: pls !!