C code that gets filename from the user and prints the contents of the file in the console...

Just another example...
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
 
int main(int argc, char const *argv[]) {
    char fileName[20];
    int fileFound = 0;
 
    // Get the filename from the user:
    int fileNameLength = read(0,fileName,19);
    // We need to get rid of the new line character caused by terminal
    // Replace the new line character with \0 
    fileName[fileNameLength-1] = fileName[fileNameLength];
 
    printf("You want to see the contents of: %s\n", fileName);
 
    // open the file:
    int fd = 0;
    fd = open(fileName,O_RDONLY);
 
    if (fd == -1) {
        // Something went wrong, perhaps no such file:
        perror(NULL);
        printf("%s\n", fileName);
    } else {
        // Read until the read method returns 0 bytes. 
        char buf[20];
        int numBytesRead = read(fd, buf, 20);
        while (numBytesRead) {
            write(1, buf, numBytesRead);
            numBytesRead = read(fd, buf, 20);
        }
        close(fd);
    }
    puts("");
}