Questions[linux]

I understand that both download and install packages, but I don't know when one works and when the other works.

I have a file with this content:

Hola qué tal
Yo \t muy bien
    Un placer.

I want to read it line by line, saving the value of each line in a variable to process it.

That is, I want:

• Read the first line.
• Carry out the assignment of the value "Hello how are you" to the variable $linea.
• Do things with $linea.
• Read the second line.
• Assign the value "I \t very well" to $linea.

And so on.

I am a beginner in Linux, and this question arose:

• Can a file or directory belong to more than one group?

It turns out that I have a process that I would like to keep open for an indefinite amount of time. If I start the process from SSH, exiting the SSH session also kills the process.

I want to know how that process can be left running even though I exit the SSH session.

Original question: Why does the C preprocessor interpret the word “linux” as the constant “1”? by ahmedaly50

Why does the preprocessor in GCC interpret the word linuxas the constant 1?

test.c

#include <stdio.h>
int main(void)
{
int linux = 5;
return 0;
}

Result of $ gcc -E test.c(for after the pre-processor stage):

int main(void)
{
int 1 = 5;
return 0;
}

Which of course produces an error.

(BTW: There is no one #define linuxin the stdio.h file)