Trouble opening a file in linux

Question

I am trying to print running processes on a linux system, but I am getting a segmentation fault when trying to do so. Here is my code:

FILE *ps;
char line[256];
char * command = "ps";  
ps = fopen(command, "r");
if(ps == NULL){
    perror("Error");
}
while(fgets(line, sizeof(line), ps)){
    printf("%s", line);
}
fclose(ps);

The odd thing is that when I use the same code but replace "ps" with "/proc/meminfo" or other files, it will correctly output. Thanks in advance for the help.

`ps` is not a file, it is a command. At least that's true based on the way you want to use it. — Vaughn Cato, Apr 10 '16 at 17:43
Yes, it says it doesn't exist. How then would I get the data from the command "ps" into a string? — user3483203, Apr 10 '16 at 17:44
Post the solution as an answer. Don't edit your question. It's totally fine to self-answer questions. — John Kugelman, Apr 10 '16 at 18:20

score 3 · Accepted Answer · answered Apr 10 '16 at 18:28

3

Try to use popen and pclose for running command rather than fopen and fclose

char line[256];
FILE *ps = popen("ps", "r");
if(ps == NULL){
    perror("Error");
}

while(fgets(line, sizeof(line), ps)){
    printf("%s", line);
}

pclose(ps);

answered Apr 10 '16 at 18:28

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Trouble opening a file in linux

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