LinuxQuestions.org - handle control characters

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shdd	04-23-2013 12:51 PM

handle control characters

I need handle control characters in my program.
this code is a simple pipe:

Code:

#include <stdio.h>

void mypipe( FILE *fd)

{

        char *buf;

        size_t linesize = 0;

        while ( ! feof (fd) )

    {

                        getline (&buf , &linesize , fd);

                        fputs( buf , stdout );

                        fflush(stdout);

        }

        fclose(fd);

}

int main(int argc, char *argv[])

{

        mypipe(stdin);

        return 0;

}

for example if I run this command:
ls --color | ./mypipe
colored text will be display. how can I Ignore escape sequences?

NevemTeve

04-24-2013 05:08 AM

use ls --color=never
your program could filter the escape-sequences, but that wouldn't be easy, because there are many different espace-sequences. See man 5 terminfo for a start.

David the H.

04-25-2013 12:45 PM

"--color" is equivalent to "--color=always". If you use "--color=auto" instead it won't insert escape sequences when the output is a pipe or file, but will add them when it detects a raw terminal.

If you have to code it, however, a simple regular expression like "\033[[][0-9;]+m" can strip out all the color codes, at least. But as NevemTeve said, it would have to be much more complex to capture all of the possible ansi escape sequences.

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