LinuxCommandLibrary

clear_console

Clear the terminal screen

SYNOPSIS

clear [options]

PARAMETERS

-T type
    Overrides the value of the TERM environment variable, explicitly specifying the terminal type for which to retrieve screen-clearing capabilities. This is rarely needed as clear usually correctly infers the type.

-V
    Prints the version information of the clear utility to standard output.

DESCRIPTION

The concept of 'clear_console' in Linux typically refers to the action of erasing all visible text from the terminal screen and repositioning the cursor to the top-left corner. While 'clear_console' itself is not a standard standalone command in most Linux distributions, this functionality is robustly provided by the clear command. clear operates by consulting the terminfo database to retrieve the correct escape sequences specific to the current terminal type, ensuring broad compatibility across various terminal emulators. Its primary purpose is to offer a clean visual slate for subsequent command execution, improving readability without typically affecting the terminal's scrollback history.

CAVEATS

The command clear_console is not a standard or pre-installed Linux command. The functionality of clearing the console is universally provided by the clear command. Users might encounter 'clear_console' in custom scripts or specific niche environments.
The clear command, while effective for the visible screen, generally does not erase the terminal's scrollback buffer; previous output can often still be viewed by scrolling up. Its effectiveness relies on the correct TERM environment variable and accurate terminfo database entries.

NOT A STANDARD COMMAND

It is crucial to understand that clear_console is not a standard executable present in most Linux distributions. The typical command for clearing the terminal screen is clear. If you encounter 'clear_console', it is likely a custom script, an alias, or a misunderstanding of a similar command.

CLEARING SCROLLBACK BUFFER

While clear effectively clears the currently visible portion of the terminal, it usually leaves the scrollback history intact. This means you can still scroll up to view previous commands and their output. To truly clear the entire buffer (including scrollback), terminal-specific escape sequences or functions might be necessary, such as `printf '\033[3J\033[H\033[2J'` for some Xterm-compatible terminals, or using your terminal emulator's built-in 'Clear Scrollback' feature.

EFFICIENCY CONSIDERATIONS

For frequent use, some shell built-ins or direct escape sequences (e.g., `echo -e '\033c'`) can be marginally faster than invoking the external clear command, as built-ins are part of the shell and avoid process creation overhead. However, clear is generally preferred for its portability and reliance on the robust terminfo system.

HISTORY

The ability to clear a terminal screen has been fundamental since the advent of video display terminals. The clear command, which facilitates this action, has been a standard utility in Unix-like operating systems for decades. Its implementation relies on the terminfo (or its predecessor, termcap) database, which was developed to abstract away the myriad of control sequences required by different terminal hardware. This abstraction allows applications like clear to function correctly across a wide array of terminal types, making it a robust and portable solution for screen management.

SEE ALSO

reset(1), tput(1), stty(1), console(4)

Copied to clipboard