What is Crunch?
Crunch is a great linux tool used for generating passwords. You can tell him what combination you need and it will generate it. If you need all the password combinations containing 6 digits and for example “abcde1234!” it will generate a file with all of them. The output from crunch can be sent to the screen, file, or to another program.
The syntax is really simple:
Code language: Bash (bash)
./crunch <from-len> <to-len> [-f <path to charset.lst> charset-name] [-o wordlist.txt or START] options: -f /path/to/charset.lst charset-name Specifies a character set from the charset.lst -o wordlist.txt Specifies the file to write the output to, eg: wordlist.txt ./crunch 8 8 -f charset.lst mixalpha-numeric-all-space -o wordlist.txt crunch should generate a 8 character wordlist using the mixalpha-number-all-space character set from charset.lst and will write the wordlist to a file named wordlist.txt. The file will start at cbdogaaa and end at " dog " For compleate manual please visit crunch man page.
Installation in Ubuntu linux
sudo apt install crunch
Installation in Debian linux
sudo apt-get install crunch
Example 1 generating a 6 digit file containing “abcde1234!”
crunch 6 6 'abcde1234!' -o exportfile.txt
Example 2 generating a 8 digit file containing special characters
Code language: PHP (php)
crunch 8 8 pentest\@\#\$\%\^\&\! -o textnum.txt
Here is a simple video using crunch
Crunch is used from penetration testing teams to generate random passwords to test wireless systems, firewalls and other IoT systems, it simple, easy to use and it’s fast.
If you are interested you can check How to generate a random password in linux using /dev/random