How To Install flex on Debian 10

Learn how to install flex on Debian 10 with this tutorial. flex is fast lexical analyzer generator

Introduction

In this tutorial we learn how to install flex on Debian 10.

What is flex

flex is:

Flex is a tool for generating scanners: programs which recognized lexical patterns in text. It reads the given input files for a description of a scanner to generate. The description is in the form of pairs of regular expressions and C code, called rules. Flex generates as output a C source file, lex.yy.c, which defines a routine yylex(). This file is compiled and linked with the -lfl library to produce an executable. When the executable is run, it analyzes its input for occurrences of the regular expressions. Whenever it finds one, it executes the corresponding C code.

There are three methods to install flex on Debian 10. We can use apt-get, apt and aptitude. In the following sections we will describe each method. You can choose one of them.

Install flex Using apt-get

Update apt database with apt-get using the following command.

sudo apt-get update

After updating apt database, We can install flex using apt-get by running the following command:

sudo apt-get -y install flex

Install flex Using apt

Update apt database with apt using the following command.

sudo apt update

After updating apt database, We can install flex using apt by running the following command:

sudo apt -y install flex

Install flex Using aptitude

If you want to follow this method, you might need to install aptitude first since aptitude is usually not installed by default on Debian. Update apt database with aptitude using the following command.

sudo aptitude update

After updating apt database, We can install flex using aptitude by running the following command:

sudo aptitude -y install flex

How To Uninstall flex on Debian 10

To uninstall only the flex package we can use the following command:

sudo apt-get remove flex

Uninstall flex And Its Dependencies

To uninstall flex and its dependencies that are no longer needed by Debian 10, we can use the command below:

sudo apt-get -y autoremove flex

Remove flex Configurations and Data

To remove flex configuration and data from Debian 10 we can use the following command:

sudo apt-get -y purge flex

Remove flex configuration, data, and all of its dependencies

We can use the following command to remove flex configurations, data and all of its dependencies, we can use the following command:

sudo apt-get -y autoremove --purge flex

Dependencies

flex have the following dependencies:

References

Summary

In this tutorial we learn how to install flex package on Debian 10 using different package management tools: apt, apt-get and aptitude.