Determine number of lines in terminal

Question

I would like to write a short d program that fills the screen with pound symbols. Here is what I have

import std.stdio;
import std.process;
import std.conv;

void main(string[] args){
  auto lines =  environment.get("LINES");
  int line_count = to!int(lines); 
  for(int a = 1; a <= line_count; a++){
    writeln("######################################################################");
  }
}

I expected this to work because when I execute "echo $LINES" from the terminal it prints "47". However, LINES appears empty when I run the program via rdmd in the same session. This is on Ubuntu Raring. Any ideas?

Can you invoke `stty size`? – Keith Thompson Aug 05 '13 at 19:26 — Keith Thompson, Aug 05 '13 at 19:26
Yes. That works. Add it as an answer and I will select it. – RedMage Aug 05 '13 at 20:53 — RedMage, Aug 05 '13 at 20:53

score 7 · Accepted Answer · edited May 23 '17 at 12:05

7

If you can grab the output of the command stty size, that's probably more reliable than examining the $LINES and $COLUMNS environment variables.

Or you can invoke the TIOCGWINSZ ioctl as described in this answer.

edited May 23 '17 at 12:05

Community

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answered Aug 05 '13 at 21:01

Keith Thompson

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score 4 · Answer 2 · answered Aug 05 '13 at 20:04

4

If you just want a simple fix, you can put export LINES COLUMNS in your ~/.bashrc to make these variables available in your program.

For a proper solution, you could try to invoke the ioctl TIOCGWINSZ, or find a D library that supports querying the terminal (such as ncurses wrappers).

answered Aug 05 '13 at 20:04

that other guy

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There are two such libraries, ycurses and dcruses. However, the easiest solution is http://stackoverflow.com/questions/1022957/getting-terminal-width-in-c . – DejanLekic Aug 05 '13 at 20:53

Determine number of lines in terminal

2 Answers2