Can I make a suggestion? You probably do not know how long the word/letter part exactly is and probably the numbers are only at the end, right?
So perhaps you can first generate the letter part using increments (-i). Note that with this example the mask will generate all letter combinations of length 1-8 with the first letter always being upper case.
./haschat.exe -a3 --stdout ?u?l?l?l?l?l?l?l -i> letters_part.txt
Then run a hybrid attack where you add the numbers again incrementing if you are not sure how many numbers.
./haschat.exe -a6 letters_part.txt ?d?d?d?d -i ....
In the above command you should still add your hash mode and other parameters. Note that if your letters are in fact a word or name and not random, that you can greatly reduce the key-space by using a dictionary and not just a random letters. See for example these dictionaries of words:
https://github.com/clem9669/wordlists
In case those digits are in fact a date, e.g. if it would start with a year, you can make a mask that looks like 19?d?d?d?d?d?d and 20?d?d?d?d?d?d again making your keyspace smaller. Hope this helpss
So perhaps you can first generate the letter part using increments (-i). Note that with this example the mask will generate all letter combinations of length 1-8 with the first letter always being upper case.
./haschat.exe -a3 --stdout ?u?l?l?l?l?l?l?l -i> letters_part.txt
Then run a hybrid attack where you add the numbers again incrementing if you are not sure how many numbers.
./haschat.exe -a6 letters_part.txt ?d?d?d?d -i ....
In the above command you should still add your hash mode and other parameters. Note that if your letters are in fact a word or name and not random, that you can greatly reduce the key-space by using a dictionary and not just a random letters. See for example these dictionaries of words:
https://github.com/clem9669/wordlists
In case those digits are in fact a date, e.g. if it would start with a year, you can make a mask that looks like 19?d?d?d?d?d?d and 20?d?d?d?d?d?d again making your keyspace smaller. Hope this helpss