Shell – Press any key to pause shell script, press again to resume

If you changed 831092,25a1bd66f2eec71aa2f0a8bb3d,/path/to/a/file to /path/to/a/file,831092,25a1bd66f2eec71aa2f0a8bb3d

You could do it with:

look /path/to/ /dev/shm/tmp.file

look is a traditional Unix utility from the 70s, not specified by POSIX but fairly common. On Debian and derivatives, you'll find one in the bsdmainutils package, there's also one in util-linux (also copied from BSD, not on the Debian package by the same name).

look mmap()s the file and does a binary search.

However note that the Debian implementation reverts to a basic linear search a la grep unless you pass the -b option (sigh). So, on Debian or derivative, you'll want:

look -b /path/to/ /dev/shm/tmp.file

Also note that some implementations have a limit on the size of the file they can handle (see corresponding bug with patch for Debian's)

Here is something I wrote now that run on each line of batch-file.txt and run youtube-dl on it.
If there is no connection to the web site you trying to download from it will loop until connection restored (you should probably need to add some timeout on it since it will not stop.)
I used curl with expected 200 status code since if this don't work you probably won't be able to download.

The content of batch-file.txt is the same as before.

Running the script:

download.sh ./batch-file.txt {download_web_site_url}
# Example:
download.sh ./batch-file.txt google.com`

#!/bin/bash
# B"H

# Insted of using youtube-dl batch-file option read the file using bash.
URLS=$1 # "batch-file.txt"
# Pass the URL for site you trying to download from.
SITE_URL=$2

# This function check if url is returning 200 status code.
check_site_connection()
{
    # curl to 'your_site_url' with -I option for only the respons info only
    # pipe the respons tp awk with 'NR < 2' so only the first line with the status code is printed.
    # Return up if respons is 200.
    if [[ $(curl -Is $SITE_URL | awk 'NR < 2 {print $2}') == "200" ]];
    then
        echo up;
    else
        echo down;
    fi
}

# read the batch-file.
while IFS= read -r line
do
    # for each line in batch-file loop until conection to site is up with 2 seconds delay.
    while [[ $(check_site_connection) == "down" ]]
    do
        echo "waiting for internet conection"
        sleep 2
    done
    # run youtube-dl where line is the url to dowmload.
    ./youtube-dl "$line"
done < "$URLS"

Edit:

Just found this in the README.md and tested it working .
This for case each line is a playlist and not separate video.

youtube-dl --download-archive archive.txt URL_TO_PLAYLIST

This will download only new videos each time you run so if you add --download-archive archive.txt to the script above in ./youtube-dl --download-archive archive.txt "$line" So if it's start again it will go over all the playlist but will only start download from where it's stops.