-a: attack mode
-a 0: Dictionnary attack 
-a 1: Combination attack (usefull when building custom list)
-m: specify type
-r: use a rule
-a 3: Mask attack (passwords with a subset)
--stdout: Print loaded passwords to stdout

Rules

Rules allows to perform operations on each password

One ruleset we could try is best64.rule, which contains 64 standard password modifications—such as appending numbers or substituting characters with their "leet" equivalents. To perform this kind of attack, we would append the -r <ruleset> option to the command, as shown below:

ls -l /usr/share/hashcat/rules

total 2852
-rw-r--r-- 1 root root 309439 Apr 24  2024 Incisive-leetspeak.rule
-rw-r--r-- 1 root root  35802 Apr 24  2024 InsidePro-HashManager.rule
-rw-r--r-- 1 root root  20580 Apr 24  2024 InsidePro-PasswordsPro.rule
-rw-r--r-- 1 root root  64068 Apr 24  2024 T0XlC-insert_00-99_1950-2050_toprules_0_F.rule
-rw-r--r-- 1 root root   2027 Apr 24  2024 T0XlC-insert_space_and_special_0_F.rule
-rw-r--r-- 1 root root  34437 Apr 24  2024 T0XlC-insert_top_100_passwords_1_G.rule
-rw-r--r-- 1 root root  34813 Apr 24  2024 T0XlC.rule
-rw-r--r-- 1 root root   1289 Apr 24  2024 T0XlC_3_rule.rule
-rw-r--r-- 1 root root 168700 Apr 24  2024 T0XlC_insert_HTML_entities_0_Z.rule
-rw-r--r-- 1 root root 197418 Apr 24  2024 T0XlCv2.rule
-rw-r--r-- 1 root root    933 Apr 24  2024 best64.rule
-rw-r--r-- 1 root root    754 Apr 24  2024 combinator.rule
-rw-r--r-- 1 root root 200739 Apr 24  2024 d3ad0ne.rule
-rw-r--r-- 1 root root 788063 Apr 24  2024 dive.rule
-rw-r--r-- 1 root root  78068 Apr 24  2024 generated.rule
-rw-r--r-- 1 root root 483425 Apr 24  2024 generated2.rule
drwxr-xr-x 2 root root   4096 Oct 19 15:30 hybrid
-rw-r--r-- 1 root root    298 Apr 24  2024 leetspeak.rule
-rw-r--r-- 1 root root   1280 Apr 24  2024 oscommerce.rule
-rw-r--r-- 1 root root 301161 Apr 24  2024 rockyou-30000.rule
-rw-r--r-- 1 root root   1563 Apr 24  2024 specific.rule
-rw-r--r-- 1 root root     45 Apr 24  2024 toggles1.rule
-rw-r--r-- 1 root root    570 Apr 24  2024 toggles2.rule
-rw-r--r-- 1 root root   3755 Apr 24  2024 toggles3.rule
-rw-r--r-- 1 root root  16040 Apr 24  2024 toggles4.rule
-rw-r--r-- 1 root root  49073 Apr 24  2024 toggles5.rule
-rw-r--r-- 1 root root  55346 Apr 24  2024 unix-ninja-leetspeak.rule

Mask attack