One (midly annoying) feature of mg is that it appends /dev/null to the
grep invocation. I guess this was done so grep is never called with
only one file argument and so it always displays the filename in its
output.
However, this gets a bit annoying when one only types "grep -n -R foo"
and yields no results because only /dev/null was consulted.
My proposal is to add -H to the mix instead.
This poses a problem: it gets too easy to "hang" mg by forgetting the
path to the files: grep would read from stdin and since inherits the
cooked mode ^D and ^C don't work. Diff below works around the problem
in the easier way: redirecting stdin from /dev/null. (a follow-up
patch could rework compile_mode and clean it up a bit, avoiding the
cd'ing back and forth too, by just forking a child and redirect its
stdout with a pipe.)
(note that this issue is already present: M-x grep RET C-u "cat -" RET)
ok?
diff /home/op/w/mg.orig
commit - b83db95072ea94d64c0bb6027c4b3478e3400e5c
path + /home/op/w/mg.orig
blob - 016256f64d06be49304999fa4665018e4f823d31
file + grep.c
--- grep.c
+++ grep.c
@@ -69,14 +69,12 @@ grep(int f, int n)
struct buffer *bp;
struct mgwin *wp;
- (void)strlcpy(cprompt, "grep -n ", sizeof(cprompt));
+ (void)strlcpy(cprompt, "grep -Hn ", sizeof(cprompt));
if ((bufp = eread("Run grep: ", cprompt, NFILEN,
EFDEF | EFNEW | EFCR)) == NULL)
return (ABORT);
else if (bufp[0] == '\0')
return (FALSE);
- if (strlcat(cprompt, " /dev/null", sizeof(cprompt)) >= sizeof(cprompt))
- return (FALSE);
if ((bp = compile_mode("*grep*", cprompt)) == NULL)
return (FALSE);
@@ -189,7 +187,7 @@ compile_mode(const char *name, const char *command)
buf = NULL;
sz = 0;
- n = snprintf(qcmd, sizeof(qcmd), "%s 2>&1", command);
+ n = snprintf(qcmd, sizeof(qcmd), "%s 2>&1 </dev/null", command);
if (n < 0 || n >= sizeof(qcmd))
return (NULL);
