commit 93c75d2bad341af383520409fd354dcff3f2c279
from: David du Colombier <0intro@gmail.com>
date: Mon Oct 01 15:20:35 2018 UTC

grep: update from Plan 9

This change fixes a segfault in grep -e when no argument
has been provided. Thanks to Sean Hinchee for reporting
this issue.

Fixes #186.

commit - de3b6d5848d5361490ed049154985d01dd5068f9
commit + 93c75d2bad341af383520409fd354dcff3f2c279
blob - d37aeb10f89fad6dd0867b371f7d8dec2c765935
blob + a847d73f5fabeee5f43e3c7932f19112aa1ababa
--- src/cmd/grep/main.c
+++ src/cmd/grep/main.c
@@ -5,7 +5,7 @@ char *validflags = "bchiLlnsv";
 void
 usage(void)
 {
-	fprint(2, "usage: grep [-%s] [-f file] [-e expr] [file ...]\n", validflags);
+	fprint(2, "usage: grep [-%s] [-e pattern] [-f patternfile] [file ...]\n", validflags);
 	exits("usage");
 }
 
@@ -31,12 +31,12 @@ main(int argc, char *argv[])
 	case 'e':
 		flags['e']++;
 		lineno = 0;
-		str2top(ARGF());
+		str2top(EARGF(usage()));
 		break;
 
 	case 'f':
 		flags['f']++;
-		filename = ARGF();
+		filename = EARGF(usage());
 		rein = Bopen(filename, OREAD);
 		if(rein == 0) {
 			fprint(2, "grep: can't open %s: %r\n", filename);