lern – The Bash Flash Card Script

Martin Döring, September 18th of 2021

I wanted to learn a new language, but I did not find a satisfying solution for that. Anki drove me crazy in it's complexity and handling. So today I wrote my own intentionally minimalistic 80 lines flash cards script in bash. I named it »lern« which is German for »learn«, as you may have assumed. ;-)

For now it is a very simple learning algorithm. The code could be enhanced to save the progress in an extra file. Also for now there is no way to learn a subset, say just 30 records from 300. Best for now would be to structure you flash card files in a way, that every file is just about 30 records long.

How it works

usage: lern [-r] filename.csv

The script works like this:

• It shows the question,
• you hit <enter> and
• you see the correct answer
• you hit <y>, if you did recall it correctly
• you hit <x> or <q> to quit
• every other input counts as »no«

The running script looks like this:

####################
English : animal
Italiano: animale
####################

q or x to quit
ok? y/N: 

CSV File Format

The file format for the vocabulary is simple: The CSV file has two columns with words or phrases to learn. Column »A« is the question asked and column »B« is the answer. Although, you can change this with the -r option and learn the other way round.

The first line of the file contains the languages to learn in column »A« and »B«. The csv file needs to be saved with embracing double quotes for every cell. The whole file looks like this, as an example:

"English";"Italiano"
"animal";"animale"
"jacket";"giacca"
"decision";"decisione"

Prerequisites

• Runs in every terminal session with a bash shell.
• One or more csv files with double quotes »"« around the single cell's text for vocabulary to learn

Features

• Reads flash card records from a normal two column csv file you can create, and maintain simply with LibreOffice Calc or Excel.
• Language pair information is read in from line one of the csv file.
• Algorithm: You need to learn as long as you got every pair right for three times.
• You can make use of as much commas or semicolons as you like
• The columns can be seperated by »;« or »,«
• You can invert the learning order with the »-r« option.

Shortcomings

• No saved state of learning progress
• No double quotes in records, use » and « for this, if needed
• Better to learn with not so long files, say 30 records

lern — The Bash Flash Card Script

#!/bin/bash

# Copyright 2021 Martin Döring
# This Code is MIT licensed: 
# https://opensource.org/licenses/mit-license.php

# Check argument count
typeset -i reverse=0
if [[ $# -eq 1 ]]; then
    file=$1
elif [[ $# -eq 2 && "$1" == "-r" ]]; then
    reverse=1
    file=$2
else
    echo "usage: lern [-r] filename.csv"
    exit 1
fi

# read in all records to learn from csv file
IFS="\""
typeset -i n=0
typeset -a fronts
typeset -a backs
typeset -ai unknown
while read d1 front d2 back d3
do
    if [[ $reverse -eq 1 ]]; then
        fronts[n]="$back"
        backs[n]="$front"
    else
        fronts[n]="$front"
        backs[n]="$back"
    fi    
    unknown[n]=3
    n=n+1
done < $file
unset IFS

# find the length of the longest column header of the two
typeset -i headlen=${#fronts[0]}
if [[ ${#backs[0]} > $headlen ]]; then
    headlen=${#backs[0]}
fi

# learn all the vocabulary, have each at least 3 times known
typeset -i count=${#fronts[@]}
typeset -i todo
while :; do
    todo=0
    for ((n=1;n<$count;n++)); do
        if [[ ${unknown[n]} > 0 ]]; then
            clear
            echo "####################"
            printf "%-${headlen}s: " "${fronts[0]}"
            echo "${fronts[n]}"
            printf "%-${headlen}s: " "${backs[0]}"
            read -s ok
            echo "${backs[n]}"
            echo "####################"
            echo
            echo "q or x to quit"
            read -n 1 -p "ok? y/N: " ok
            
            if [[ "$ok" == "q" || "$ok" == "x" ]]; then
                echo "See you next time ..."
                exit 0
            elif [[ "$ok" == "y" ]]; then
                unknown[n]=${unknown[n]}-1
            fi
            if [[ ${unknown[n]} > 0 ]]; then
                todo=1
            fi
        fi
    done
    if [[ $todo == 0 ]]; then
        clear
        echo "Congratulation, you are done for today!"
        break
    fi
done

If you have any suggestions, how to make the script even smaller or faster, just write me:

Martin Döring

——

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