It is possible to use a mask attack (like with oclHashcat) in hashcat-cli, to do it you will need maskprocessor, the ability to use mkfifo (it probably won't work on windows) and obviously hashcat.

I'll assume you are in your hashcat directory and maskprocessor is in the higher directory, in maskprocessor-0.65/.

$ mkfifo dict

This will create a 'fifo' called 'dict'

Then we use :

$ ../maskprocessor-0.65/mp64.bin -o dict ?l?l?l?l?d?d?d?d

And in another shell (or screen session) :

$ ./hashcat-cli64.bin -m 0 -n 2 -c 512 -o found.txt hashes.txt dict

../maskprocessor-0.65/mp64.bin -o dict ?l?l?l?l?d?d?d?d

With maskprocessor we generate all the possible combinations with the mask ?l?l?l?l?d?d?d?d (4 lowercase chars followed by 4 digits) and tell it to output these combinations in our fifo 'dict'

./hashcat-cli64.bin -m 0 -n 2 -c 512 -o found.txt hashes.txt dict

Then we launch hashcat-cli with our fifo as it was a normal dict file.

And hopefully you will get an output looking like this :

Added hashes from file hashes.txt: 5142830 (1 salts)

Wordlist..: dict
Index.....: 1/1 (segment), 59651869 (words), 536866821 (bytes)
Recovered.: 0/5142830 hashes, 0/1 salts
Speed/sec.: 7.96M plains, 7.96M words
Progress..: 59651869/59651869 (100.00%)
Running...: 00:00:00:08
Estimated.: --:--:--:--

[...]

Wordlist..: dict
Index.....: 77/1 (segment), 36217956 (words), 325961604 (bytes)
Recovered.: 19/5142830 hashes, 0/1 salts
Speed/sec.: 5.57M plains, 5.57M words
Progress..: 36217956/36217956 (100.00%)
Running...: 00:00:00:06
Estimated.: --:--:--:--

(Note the Indexes numbers :p)