Fake CNPJ - Shell-Bash

Introduction

As a programmer, sometimes you may encounter situations where you need to generate random CNPJs (Cadastro Nacional de Pessoa Jurídica), which is an identification number for Brazilian companies. In this project, we will create a Bash function that generates random CNPJs for test or dummy data purposes.

Requirements

• Bash shell (version 4+)
• sed
• awk

Implementation

The Bash function fake_cnpj generates a random CNPJ following the Brazilian format: XX.XXX.XXX/XXXX-XX. The structure of the CNPJ is as follows:

|  XX  |  XXX  |  XXX  | XXXX |  XX  |
|------|-------|-------|------|------|
| Root | Branch| Branch| Code |  DV  |

Code

function fake_cnpj(){
  cnpj=$(echo $((RANDOM % 90000000 + 10000000))$((RANDOM % 90000 + 10000)))
  root=$(echo $cnpj | cut -c 1-8)
  branch=$(echo $cnpj | cut -c 9-11)
  code=$(echo $cnpj | cut -c 12-15)

  d1=$((($root / 1000000) * 5 + (($root % 1000000) / 100000) * 4 + (($root % 100000) / 10000) * 3 + (($root % 10000) / 1000) * 2 + (($root % 1000) / 100) * 9 + (($root % 100) / 10) * 8 + ($root % 10) * 7))
  d2=$((($branch / 10) * 9 + ($branch % 10) * 8 + $d1))
  dv1=$((11 - ($d2 % 11)))

  if [ $dv1 -ge 10 ]; then
    dv1=0
  fi

  d3=$((($code / 1000) * 2 + (($code % 1000) / 100) * 9 + (($code % 100) / 10) * 8 + ($code % 10) * 7))
  dv2=$((11 - (($d2 * 10 + $dv1 + $d3) % 11)))

  if [ $dv2 -ge 10 ]; then
    dv2=0
  fi

  echo "${root:0:2}.${root:2:3}.${root:5:3}/${branch}-${dv1}${dv2}"
}

Example usage

$ fake_cnpj
42.097.563/8564-90

Conclusion

In this project, we have created a Bash function fake_cnpj that generates random CNPJs following the Brazilian format. This can be useful for generating test or dummy data for your applications.