fix "tail -10b"

SCCS-vsn: usr.bin/tail/tail.c 4.5

diff --git a/usr/src/usr.bin/tail/tail.c b/usr/src/usr.bin/tail/tail.c
index fd48473..4a7b2fd 100644 (file)
--- a/usr/src/usr.bin/tail/tail.c
+++ b/usr/src/usr.bin/tail/tail.c
@@ -1,4 +1,4 @@
-static char *sccsid = "@(#)tail.c      4.4 (Berkeley) %G%";
+static char *sccsid = "@(#)tail.c      4.5 (Berkeley) %G%";

 /* tail command 
  *
  *     tail where [file]
 /* tail command 
  *
  *     tail where [file]


@@ -20,7 +20,9 @@ static char *sccsid = "@(#)tail.c     4.4 (Berkeley) %G%";
 #include       <sys/stat.h>
 #include       <errno.h>
 
 #include       <sys/stat.h>
 #include       <errno.h>
 

-#define LBIN 4097
+#define LBIN 8193
+#undef BUFSIZ
+#define        BUFSIZ  LBIN-1

 struct stat    statb;
 int    follow;
 int    piped;
 struct stat    statb;
 int    follow;
 int    piped;


@@ -66,6 +68,7 @@ char **argv;
        switch(*arg++) {
 
        case 'b':
        switch(*arg++) {
 
        case 'b':

+               if (n == -1) n = 1;

                n <<= 9;
                if(bylines!=-1) goto errcom;
                bylines=0;
                n <<= 9;
                if(bylines!=-1) goto errcom;
                bylines=0;


@@ -135,7 +138,8 @@ keep:
                fexit();
        if(!piped) {
                fstat(0,&statb);
                fexit();
        if(!piped) {
                fstat(0,&statb);

-               di = !bylines&&n<LBIN?n:LBIN-1;
+               /* If by lines, back up 1 buffer: else back up as needed */
+               di = bylines?BUFSIZ:n;

                if(statb.st_size > di)
                        lseek(0,-di,2);
                if(!bylines)
                if(statb.st_size > di)
                        lseek(0,-di,2);
                if(!bylines)