pollev/bash_progress_bar

APT like progress bar

bash_progress_bar

Note: There is now also this python implementation

This script is intended to be sourced by other bash scripts. It will allow those scripts to create a progress bar which does not interfere with the scrolling output of the script. The look and feel for this progress bar is based on the progress bar used by APT.

What makes this progress bar different from the basic terminal progress bars which use carriage return (\r) to overwrite their own line, is that this progress bar does not interfere with the normal output of your script. This makes it very easy to update existing scripts to use this bar without having to worry about the scrolling of your output.

An example can be viewed in test_bar.sh. The actual implementation can be found in progress_bar.sh

Example output:

bash_progress_bar's Issues

harmonize bar with completed process

Hi, thanks for this nice tool.
How can I stop the progress bar if the primary output file has been created faster than expected?
Best wishes

Progress bar disappears when terminal is resized

After trying out the script for a bit I noticed that when your try to resize the terminal when progress bar is running it disappears / moves up from the bottom.

OS: Ubuntu 20.04
Terminal: gnome-terminal
Shell: bash

Error when running

I get this;
progress_bar.sh: 29: progress_bar.sh: Syntax error: "(" unexpected
when I run the program. What did I do wrong?

Not working as expected on MacOS (Bash)

I thought perhaps it was my implementation that was incorrect but it seems something it clearly not playing nicely with macos.

I took your script and put it all in one shell script file for testing.
I had to remove the head -c lines for the fake output but besides that, the code is unaltered. (removed comments for brevity)

#!/bin/bash

# Constants
CODE_SAVE_CURSOR="\033[s"
CODE_RESTORE_CURSOR="\033[u"
CODE_CURSOR_IN_SCROLL_AREA="\033[1A"
COLOR_FG="\e[30m"
COLOR_BG="\e[42m"
COLOR_BG_BLOCKED="\e[43m"
RESTORE_FG="\e[39m"
RESTORE_BG="\e[49m"

# Variables
PROGRESS_BLOCKED="false"
TRAPPING_ENABLED="false"
TRAP_SET="false"

CURRENT_NR_LINES=0

setup_scroll_area() {
    # If trapping is enabled, we will want to activate it whenever we setup the scroll area and remove it when we break the scroll area
    if [ "$TRAPPING_ENABLED" = "true" ]; then
        trap_on_interrupt
    fi

    lines=$(tput lines)
    CURRENT_NR_LINES=$lines
    let lines=$lines-1
    # Scroll down a bit to avoid visual glitch when the screen area shrinks by one row
    echo -en "\n"

    # Save cursor
    echo -en "$CODE_SAVE_CURSOR"
    # Set scroll region (this will place the cursor in the top left)
    echo -en "\033[0;${lines}r"

    # Restore cursor but ensure its inside the scrolling area
    echo -en "$CODE_RESTORE_CURSOR"
    echo -en "$CODE_CURSOR_IN_SCROLL_AREA"

    # Start empty progress bar
    draw_progress_bar 0
}

destroy_scroll_area() {
    lines=$(tput lines)
    # Save cursor
    echo -en "$CODE_SAVE_CURSOR"
    # Set scroll region (this will place the cursor in the top left)
    echo -en "\033[0;${lines}r"

    # Restore cursor but ensure its inside the scrolling area
    echo -en "$CODE_RESTORE_CURSOR"
    echo -en "$CODE_CURSOR_IN_SCROLL_AREA"

    # We are done so clear the scroll bar
    clear_progress_bar

    # Scroll down a bit to avoid visual glitch when the screen area grows by one row
    echo -en "\n\n"

    # Once the scroll area is cleared, we want to remove any trap previously set. Otherwise, ctrl+c will exit our shell
    if [ "$TRAP_SET" = "true" ]; then
        trap - INT
    fi
}

draw_progress_bar() {
    percentage=$1
    lines=$(tput lines)
    let lines=$lines

    # Check if the window has been resized. If so, reset the scroll area
    if [ "$lines" -ne "$CURRENT_NR_LINES" ]; then
        setup_scroll_area
    fi

    # Save cursor
    echo -en "$CODE_SAVE_CURSOR"

    # Move cursor position to last row
    echo -en "\033[${lines};0f"

    # Clear progress bar
    tput el

    # Draw progress bar
    PROGRESS_BLOCKED="false"
    print_bar_text $percentage

    # Restore cursor position
    echo -en "$CODE_RESTORE_CURSOR"
}

block_progress_bar() {
    percentage=$1
    lines=$(tput lines)
    let lines=$lines
    # Save cursor
    echo -en "$CODE_SAVE_CURSOR"

    # Move cursor position to last row
    echo -en "\033[${lines};0f"

    # Clear progress bar
    tput el

    # Draw progress bar
    PROGRESS_BLOCKED="true"
    print_bar_text $percentage

    # Restore cursor position
    echo -en "$CODE_RESTORE_CURSOR"
}

clear_progress_bar() {
    lines=$(tput lines)
    let lines=$lines
    # Save cursor
    echo -en "$CODE_SAVE_CURSOR"

    # Move cursor position to last row
    echo -en "\033[${lines};0f"

    # clear progress bar
    tput el

    # Restore cursor position
    echo -en "$CODE_RESTORE_CURSOR"
}

print_bar_text() {
    local percentage=$1
    local cols=$(tput cols)
    let bar_size=$cols-17

    local color="${COLOR_FG}${COLOR_BG}"
    if [ "$PROGRESS_BLOCKED" = "true" ]; then
        color="${COLOR_FG}${COLOR_BG_BLOCKED}"
    fi

    # Prepare progress bar
    let complete_size=($bar_size*$percentage)/100
    let remainder_size=$bar_size-$complete_size
    progress_bar=$(echo -ne "["; echo -en "${color}"; printf_new "#" $complete_size; echo -en "${RESTORE_FG}${RESTORE_BG}"; printf_new "." $remainder_size; echo -ne "]");

    # Print progress bar
    echo -ne " Progress ${percentage}% ${progress_bar}"
}

enable_trapping() {
    TRAPPING_ENABLED="true"
}

trap_on_interrupt() {
    # If this function is called, we setup an interrupt handler to cleanup the progress bar
    TRAP_SET="true"
    trap cleanup_on_interrupt INT
}

cleanup_on_interrupt() {
    destroy_scroll_area
    exit
}

printf_new() {
    str=$1
    num=$2
    v=$(printf "%-${num}s" "$str")
    echo -ne "${v// /$str}"
}

generate_some_output_and_sleep() {
    echo "Here is some output"
    echo "Here is some output"
    echo "Here is some output"
    echo "Here is some output"
    echo "Here is some output"
    echo -e "\n\n------------------------------------------------------------------"
    echo -e "\n\n Now sleeping briefly \n\n"
    sleep 0.3
}


main() {
    # Make sure that the progress bar is cleaned up when user presses ctrl+c
    enable_trapping
    # Create progress bar
    setup_scroll_area
    for i in {1..99}
    do
        if [ $i = 50 ]; then
            echo "waiting for user input"
            block_progress_bar $i
            read -p "User input: "
        else
            generate_some_output_and_sleep
            draw_progress_bar $i
        fi
    done
    destroy_scroll_area
}

main

Progress bar not working in mosh shell

Is your feature request related to a problem? Please describe.
The progress bar doesn't work in mosh. Mosh is a alternative low-latency tty like ssh session. It tries to replicate how it would look in tty.

Additional context
It is something with new lines in it, because the progress bar is there, but it gets covered by the script outputting text.