Imported from ../bash-2.0.tar.gz.

examples/loadables/head.c

@@ -0,0 +1,143 @@
+/* head - copy first part of files. */
+
+/* See Makefile for compilation details. */
+
+#include "config.h"
+
+#include "bashtypes.h"
+#include "posixstat.h"
+#include "filecntl.h"
+
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif
+
+#include "bashansi.h"
+
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+
+#include "builtins.h"
+#include "shell.h"
+#include "bashgetopt.h"
+
+#if !defined (errno)
+extern int errno;
+#endif
+
+static void
+munge_list (list)
+     WORD_LIST *list;
+{
+  WORD_LIST *l, *nl;
+  WORD_DESC *wd;
+  char *arg;
+
+  for (l = list; l; l = l->next)
+    {
+      arg = l->word->word;
+      if (arg[0] != '-' || arg[1] == '-' || (isdigit(arg[1]) == 0))
+        return;
+      /* We have -[0-9]* */
+      wd = make_bare_word (arg+1);
+      nl = make_word_list (wd, l->next);
+      l->word->word[1] = 'n';
+      l->word->word[2] = '\0';
+      l->next = nl;
+      l = nl;	/* skip over new argument */
+    }
+}
+
+static int
+file_head (fp, cnt)
+     FILE *fp;
+     int cnt;
+{
+  int ch;
+
+  while (cnt--)
+    {
+      while ((ch = getc (fp)) != EOF)
+	{
+	  if (putchar (ch) == EOF)
+	    {
+	      builtin_error ("write error: %s", strerror (errno));
+	      return EXECUTION_FAILURE;
+	    }
+	  if (ch == '\n')
+	    break;
+	}
+    }
+}
+
+head_builtin (list)
+     WORD_LIST *list;
+{
+  int nline, opt, rval;
+  WORD_LIST *l;
+  FILE *fp;
+
+  char *t;
+
+  munge_list (list);	/* change -num into -n num */
+
+  reset_internal_getopt ();
+  nline = 10;
+  while ((opt = internal_getopt (list, "n:")) != -1)
+    {
+      switch (opt)
+	{
+	case 'n':
+	  nline = atoi (list_optarg);
+	  if (nline <= 0)
+	    {
+	      builtin_error ("bad line count: %s", list_optarg);
+	      return (EX_USAGE);
+	    }
+	  break;
+	default:
+	  builtin_usage ();
+	  return (EX_USAGE);
+	}
+    }
+  list = loptend;
+
+  if (list == 0)
+    return (file_head (stdin, nline));
+
+  for (rval = EXECUTION_SUCCESS, opt = 1, l = list; l; l = l->next)
+    {
+      fp = fopen (l->word->word, "r");
+      if (fp == NULL)
+	{
+	  builtin_error ("%s: %s", l->word->word, strerror (errno));
+	  continue;
+	}
+      if (list->next)	/* more than one file */
+	{
+	  printf ("%s==> %s <==\n", opt ? "" : "\n", l->word->word);
+	  opt = 0;
+	}
+      rval = file_head (fp, nline);
+      fclose (fp);
+    }
+   
+  return (rval);
+}
+
+char *head_doc[] = {
+	"Copy the first N lines from the input files to the standard output.",
+	"N is supplied as an argument to the `-n' option.  If N is not given,",
+	"the first ten lines are copied.",
+	(char *)NULL
+};
+
+struct builtin head_struct = {
+	"head",			/* builtin name */
+	head_builtin,		/* function implementing the builtin */
+	BUILTIN_ENABLED,	/* initial flags for builtin */
+	head_doc,		/* array of long documentation strings. */
+	"head [-n num] [file ...]", /* usage synopsis; becomes short_doc */
+	0			/* reserved for internal use */
+};