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Your Ultra Shell - A Beginner's Guide

Your Ultra shell provides command-line access to your Ultra service. You can use it to navigate directories, manage files, inspect storage usage, control supported applications, and run command-line utilities.

This beginner’s guide introduces the Bash shell and the commands required for common tasks. If you have not connected yet, follow Connect to your Ultra slot via SSH.

Do not install or run a custom shell: Ultra’s configured Bash environment is required for application-management commands and other service functionality. Do not replace it with Zsh, Fish, Eshell, or another shell.

Understand Your Home Directory

After you connect with SSH, Bash normally places you in your home directory.

Display your current directory:

pwd

The output normally uses the following format:

/home/<username>

Display the home directory configured for your account:

printf '%s\n' "$HOME"

Return to your home directory from any location:

cd

You can also use:

cd ~

The tilde (~) and the $HOME environment variable both represent your home directory. Prefer them over hardcoded paths in commands and scripts.

Understand Logical and Physical Paths

Your displayed home directory can be a symbolic link to another location on the server.

Display the logical path:

pwd -L

Resolve symbolic links and display the physical path:

pwd -P

Use the logical home path: The physical path can differ between servers. Do not copy the path returned by pwd -P into application configurations or scripts. Use ~, $HOME, or /home/<username> when a documented absolute path is required.

Preserve Default Files and Directories

Your home directory contains files and directories required by your Ultra service. Core items commonly include:

~/.bashrc
~/.profile
~/bin
~/downloads
~/media
~/www
Installed applications also store configuration and operational data in locations such as ~/.apps.

Do not delete Ultra-managed files: Do not delete or replace .bashrc, .profile, or Ultra-managed application directories. Altering these files can prevent the shell from initializing correctly and can interfere with application installation or management.

If required files were deleted, follow Restore Default File/Folder Structure.

Display Hidden Files

Names beginning with a period (.) are hidden by default. Examples include .bashrc, .profile, .ssh, and .apps.
Display regular and hidden entries:

ls -la

Display sizes in a human-readable format:

ls -lah

Navigate Directories

Change Directories

Use cd followed by a directory path:

cd <directory>

Open the media directory in your home directory:

cd ~/media

Move to the parent directory:

cd ..

Move up two directory levels:

cd ../..

Return to the previous directory:

cd -

Linux paths use the following references:

~ represents your home directory.
. represents the current directory.
.. represents the parent directory.
/ represents the filesystem root.

List Directory Contents

List entries in the current directory:

ls

List entries in another directory:

ls ~/media

Include hidden entries and detailed information:

ls -lah

Use Tab Completion

Enter the first part of a file, directory, or command name and press Tab.
Bash completes the name when there is one match or displays possible matches when there are several. Tab completion reduces typing errors and helps with names containing spaces or special characters.

Work With Paths Safely

Linux file and directory names can contain spaces. Enclose these paths in quotation marks:

cd "$HOME/media/TV Shows"

mv "Movie One.mkv" "$HOME/media/"

Use -- before a file name that could begin with a hyphen:

rm -- "-example.txt"

Shell wildcards require care:

matches visible entries.
A command using directory/* does not include hidden files.
Review wildcard matches before using them with mv, cp, or rm.

Create Files and Directories

Create a directory:

mkdir <directory>

Create parent directories when required:

mkdir -p "$HOME/media/Movies"

Create an empty file:

touch <filename>

Move and Rename Files

Use mv to move or rename a file or directory.

Move a file:

mv "Movie1.mkv" "$HOME/media/"

Rename a file:

mv "Movie1.mkv" "Movie 1.mkv"

Prompt before overwriting an existing destination:

mv -i "Movie1.mkv" "$HOME/media/"

If the destination is an existing directory, mv places the source inside it. If the destination does not exist, mv renames the source.

Copy Files and Directories

Use cp to copy files and directories.

Copy a file:

cp "Movie1.mkv" "$HOME/media/"

Prompt before overwriting an existing file:

cp -i "Movie1.mkv" "$HOME/media/"

Copy a directory and its contents:

cp -a "$HOME/media" "$HOME/media-backup"

The -a option preserves the directory structure and common file attributes while copying recursively.

Delete Files and Directories

Deleted files cannot normally be recovered: The Linux shell does not provide a recycle bin for files deleted with rm. Confirm the complete path before running the command. Do not execute a command containing rm unless you understand exactly what it will delete.

Prompt before deleting a file:

rm -i <filename>

Delete an empty directory:

rmdir <directory>

Review and delete a directory recursively:

rm -rI <directory>

Avoid rm -rf as a beginner: This command recursively deletes content without confirmation. An incorrect path can cause extensive and permanent data loss.

Extract Archives

Extract a ZIP Archive

Open the directory containing the archive:

cd /path/to/archive

Extract the archive into the current directory:

unzip archive-name.zip

Extract the archive into a specified directory:

unzip archive-name.zip -d /path/to/destination

List the archive’s contents without extracting it:

unzip -l archive-name.zip

Extract a RAR Archive

Extract a RAR archive:

unrar x archive-name.rar

List its contents without extracting it:

unrar l archive-name.rar

Get Command Help

Many commands provide short usage instructions through --help:

ls --help

For a complete manual page, use man:

man ls

While viewing a manual page:

Press / and enter a keyword to search.
Press n to find the next match.
Press q to exit.
Press Ctrl+C to interrupt most running terminal commands.

For additional utilities available on Ultra servers, see List of Pre-Installed Tools.

Run Long Tasks Safely

A normal foreground command can stop when its SSH session disconnects. Use screen or tmux for a long-running interactive task.
Create a named screen session:

screen -S <session-name>

Create a named tmux session:

tmux new -s <session-name>

Display help for either utility:

screen --help
tmux --help

Do not use nohup, screen, or tmux as a substitute for a properly configured application service when an application provides one.

Manage Ultra Applications

Ultra provides app-<appname> commands for supported applications. Replace <appname> with the application’s command name.
Display the available operations:

app-<appname> help

Start an application:

app-<appname> start

Stop an application:

app-<appname> stop

Restart an application:

app-<appname> restart

Repair an application when supported:

app-<appname> repair

Check the available operations: Supported commands can differ between applications. Run app-<appname> help before using an unfamiliar operation.

Use the User Control Panel for normal application installation, uninstallation, updates, and repairs unless an application guide or Ultra support instructs you to use a shell command.

Check Storage Usage

Inspect Files and Directories

Use ncdu to identify the files and directories using storage space:

ncdu -x ~

Use the arrow keys to navigate.
Press Enter to open a directory.
Press d to request deletion of the selected item.
Press q to exit.

Review the selected path carefully before confirming a deletion in ncdu. Files deleted through ncdu cannot normally be recovered from a recycle bin.

See the NCDU guide for detailed instructions.

View Disk and Traffic Statistics

Display the recorded disk and traffic statistics:

app-stats show

Display the available filters and periods:

app-stats show --help

For more information, see Disk/Traffic Usage Command.

Understand Service Restrictions

Your Ultra shell is an unprivileged user environment.

Install custom software only inside your home directory.
Do not expect root or unrestricted sudo access.
Do not attempt to install Docker or software that requires privileged kernel or system changes.
Keep custom applications within your plan’s CPU, memory, disk, and traffic limits.
Follow the application developer’s documentation and Ultra’s policies.
Be aware that Ultra support may not troubleshoot unsupported custom applications.

Troubleshooting

Restore a Broken Shell Environment

A missing or damaged .bashrc or .profile can affect the shell prompt, environment variables, and application-management commands.

Do not create replacement startup files from an unverified internet source.
Exit the current SSH session:

exit

Reconnect through SSH to confirm that the issue persists.
Follow Restore Default File/Folder Structure.
Contact Ultra support if the problem continues.

Resolve a Command Not Found Error

If Bash reports that a command was not found:

Confirm the command’s spelling and capitalization.
Check whether the command is available:

command -v <command>

Reload your profile if you recently changed it:

source ~/.profile

Reconnect through SSH and try the command again.
Consult the relevant Ultra application or utility guide.

If you require further assistance, you can open a support ticket here.