mntpart

# mntpart - mount & view a partition from a disk image file
# (C) 2015 Gunnar Andersson
# License: MPLv2

mntpart ()
{
    function _mntpartusage ()
    {
        echo "Usage: mntpart <file> <partition-number> [mountpoint]";
        echo "(Default mountpoint is /mnt)"
    };
    file=$1;
    n=$2;
    mountpoint=$3;
    [ -z "$n" ] && {
        echo "mntpart: No partition number specified";
        _mntpartusage;
        return 1
    };
    [ -z "$file" ] && {
        echo "mntpart: No image file specified";
        _mntpartusage;
        return 1
    };
    [ -z "$mountpoint" ] && mountpoint=/mnt;
    [ -e "$mountpoint" -a ! -d "$mountpoint" ] && {
        echo "Mountpoint exists but is not a directory! Giving up. ";
        return 1
    };
    [ -d "$mountpoint" ] || {
        echo "Mountpoint does not exist, creating.";
        mkdir -p $mountpoint || return 2
    };
    offset=$(fdisk -l "$file" | skip_at_beginning 9 | sed 's/*//' | pick $n | awk '{print $2}');
    byte=$(($offset*512));
    echo "Partition $n starts at sector $offset = byte $byte";
    cmd="sudo mount -o offset=$byte $file $mountpoint";
    echo "$cmd";
    $cmd;
    echo "Listing contents of $mountpoint : ";
    \ls -F --color -al $mountpoint
}

Oh sorry, this was missing. Maybe something more, IDK
skip_at_beginning ()
{
tail -n +$1
}

pick ()
{
awk "NR==$1"
}

For convenience, you might also consider setting up passwordless sudo access to mount command, assuming you're OK with the security aspect. If you're not OK with that, create a safe wrapper for mount that forces mountpoint to /mnt, for example.