diff --git a/src/main.c b/src/main.c
index 169ffff..762bcd2 100644
--- a/src/main.c
+++ b/src/main.c
@@ -833,10 +833,7 @@ int args_from_file(
   dstring* utfile_str,
   char* file_str
 ){
-  char* line;
-  unsigned int len=256;
-  unsigned int pos=0;
-  char* line_realloc;
+  dstring line;
   char c;
 
   // open file
@@ -847,7 +844,7 @@ int args_from_file(
   }
 
   // allocate line buffer
-  line=calloc(sizeof(char), len);
+  dstring_init(&line,64);
 
   while(1){
     c=fgetc(file);
@@ -861,11 +858,11 @@ int args_from_file(
     if(c=='\n' || c=='\r'){
       // read entry
       // ignore lines with fewer than three characters
-      if(pos>=3){
+      if(line.length>=3){
 	// find line starting with "#!"
-	if(line[0]=='#' && line[1]=='!'){
+	if(line.string[0]=='#' && line.string[1]=='!'){
 	  wordexp_t pwordexp;
-	  wordexp(line+2,&pwordexp,0);
+	  wordexp(line.string+2,&pwordexp,0);
 	  // read arguments
 	  read_args(pwordexp.we_wordc, (const char **)pwordexp.we_wordv, params, command, nthreads, savefile_str, utfile_str, NULL);
 	  wordfree(&pwordexp);
@@ -873,32 +870,15 @@ int args_from_file(
 	  break;
 	}
       }
-
       // reset buffer
-      pos=0;
-      line[pos]='\0';
+      line.length=0;
     }
     // add to buffer
     else {
-      // check that there is room in buffer
-      if(pos==len){
-	// too short: reallocate
-	line_realloc=calloc(sizeof(char), 2*len);
-	for(pos=0;pos<len;pos++){
-	  line_realloc[pos]=line[pos];
-	}
-	free(line);
-	line=line_realloc;
-	len=2*len;
-      }
-
-      // add c to line
-      line[pos]=c;
-      pos++;
-      line[pos]='\0';
+      dstring_append(c,&line);
     }
   }
-  free(line);
+  dstring_free(line);
   // close file
   fclose(file);