How to assign input (from echo command) in char array in C program

Question

How to assign input of echo in char array in C program? For example:

$ echo "Hello, world!" | ./hello

I need to save string "Hello, world" to an array.

read from stdin. See [this question](http://stackoverflow.com/questions/15883568/reading-from-stdin). — Catweazle, Oct 16 '16 at 19:09
@Catweazle: that question is about using the `read()` system call, which is certainly doable, but not necessary. There are ways to do it using the standard I/O library (``) that are probably more appropriate at this stage. — Jonathan Leffler, Oct 16 '16 at 19:49
Please read "[ask]", "[mcve]" and “[How much research effort is expected of Stack Overflow users?](http://meta.stackoverflow.com/q/261592)”. We need to see your attempt at solving this along with why that didn't work. Without that it looks like you want us to write the code for you. — the Tin Man, Oct 16 '16 at 20:02

score 1 · Answer 1 · edited May 23 '17 at 10:27

The output of echo is piped to the input of hello. To get a string as an input in C, use fgets: http://www.cplusplus.com/reference/cstdio/fgets/. Here is some example code:

hello.c:

#include <stdio.h>
#include <string.h>

int main() {
  char inputarr[256];
  fgets(inputarr, 256, stdin);

  //Credit to Tim Čas for the following code to remove the trailing newline
  inputarr[strcspn(inputarr, "\n")] = 0;

  printf("Value of inputarr: \"%s\"\n", inputarr);
}

Here is Tim's post about his code

Shell command:

$ gcc hello.c
$ echo "Hello, world!" | ./a.out
Value of inputarr: "Hello, world!"
$

How to assign input (from echo command) in char array in C program

1 Answers1