title: warning: unknown escape sequence '\
body: <p>I'm trying to run a regex through a system command in the code, I have gone through the threads in StackOverflow on similar warnings but I couldn't understand on how to fix the below warnings, it seems to come only for the closed brackets on doing \\}. The warnings seem to disappear but not able to get the exact output in the redirected file.</p>
  
  <pre><code>#include&lt;stdio.h&gt;
  
  
  int main(){
  
          FILE *in;
          char buff[512];
  
  if(system("grep -o '[0-9]\{1,3\}\\.[0-9]\{1,3\}\\.[0-9]\{1,3\}\\.[0-9]\{1,3\}' /home/santosh/Test/text &gt;t2.txt") &lt; 0){
                  printf("system failed:");
                  exit(1);
          }
  }
  </code></pre>
  
  <p>Warnings: </p>
  
  <pre><code>dup.c:9:11: warning: unknown escape sequence '\}'
  dup.c:9:11: warning: unknown escape sequence '\}'
  dup.c:9:11: warning: unknown escape sequence '\}'
  dup.c:9:11: warning: unknown escape sequence '\}'
  dup.c: In function 'main':
  </code></pre>