cos

Backslashes are primarily used as an escape character.

Eg. in C the following piece of code

#include <stdio.h>

int main(void)
{
printf("This\nis\ta\ntest.\n");
return 0;
}

would show the following result

This
is a
test.

the escape character being the \ and the n then standing for "a new line" or t standing for "a tab".