added read to 9base

Makefile

@@ -4,7 +4,7 @@
 include config.mk
 
 SUBDIRS  = lib9 yacc awk basename bc dc cat cleanname date echo grep mk \
-		   rc sed seq sleep sort tee test touch tr uniq
+		   rc read sed seq sleep sort tee test touch tr uniq
 
 all:
 	@echo 9base build options:

read/Makefile

@@ -0,0 +1,6 @@
+# read - read unix port from plan9
+# Depends on ../lib9
+
+TARG      = read
+
+include ../std.mk

read/read.1

@@ -0,0 +1,108 @@
+.TH CAT 1
+.SH NAME
+cat, read, nobs \- catenate files
+.SH SYNOPSIS
+.B cat
+[
+.I file ...
+]
+.br
+.B read
+[
+.B -m
+] [
+.B -n
+.I nline
+] [
+.I file ...
+]
+.br
+.B nobs
+[
+.I file ...
+]
+.SH DESCRIPTION
+.I Cat
+reads each
+.I file
+in sequence and writes it on the standard output.
+Thus
+.IP
+.L
+cat file
+.LP
+prints a file and
+.IP
+.L
+cat file1 file2 >file3
+.LP
+concatenates the first two files and places the result
+on the third.
+.PP
+If no
+.I file
+is given,
+.I cat 
+reads from the standard input.
+Output is buffered in blocks matching the input.
+.PP
+.I Read
+copies to standard output exactly one line from the named
+.IR file ,
+default standard input.
+It is useful in interactive
+.IR rc (1)
+scripts.
+.PP
+The
+.B -m
+flag causes it to continue reading and writing multiple lines until end of file;
+.B -n
+causes it to read no more than
+.I nline
+lines.
+.PP
+.I Read
+always executes a single
+.B write
+for each line of input, which can be helpful when
+preparing input to programs that expect line-at-a-time data.
+It never reads any more data from the input than it prints to the output.
+.PP
+.I Nobs
+copies the named files to
+standard output except that it removes all backspace
+characters and the characters that precede them.
+It is useful to use as
+.B $PAGER
+with the Unix version of
+.IR man (1)
+when run inside a
+.I win
+(see
+.IR acme (1))
+window.
+.SH SOURCE
+.B \*9/src/cmd/cat.c
+.br
+.B \*9/src/cmd/read.c
+.br
+.B \*9/bin/nobs
+.SH SEE ALSO
+.IR cp (1)
+.SH DIAGNOSTICS
+.I Read
+exits with status
+.B eof
+on end of file or, in the
+.B -n
+case, if it doesn't read
+.I nlines
+lines.
+.SH BUGS
+Beware of
+.L "cat a b >a"
+and
+.LR "cat a b >b" ,
+which
+destroy input files before reading them.

read/read.c

@@ -0,0 +1,91 @@
+#include <u.h>
+#include <libc.h>
+
+int	multi;
+int	nlines;
+char	*status = nil;
+
+int
+line(int fd, char *file)
+{
+	char c;
+	int m, n, nalloc;
+	char *buf;
+
+	nalloc = 0;
+	buf = nil;
+	for(m=0; ; ){
+		n = read(fd, &c, 1);
+		if(n < 0){
+			fprint(2, "read: error reading %s: %r\n", file);
+			exits("read error");
+		}
+		if(n == 0){
+			if(m == 0)
+				status = "eof";
+			break;
+		}
+		if(m == nalloc){
+			nalloc += 1024;
+			buf = realloc(buf, nalloc);
+			if(buf == nil){
+				fprint(2, "read: malloc error: %r\n");
+				exits("malloc");
+			}
+		}
+		buf[m++] = c;
+		if(c == '\n')
+			break;
+	}
+	if(m > 0)
+		write(1, buf, m);
+	free(buf);
+	return m;
+}
+
+void
+lines(int fd, char *file)
+{
+	do{
+		if(line(fd, file) == 0)
+			break;
+	}while(multi || --nlines>0);
+}
+
+void
+main(int argc, char *argv[])
+{
+	int i, fd;
+	char *s;
+
+	ARGBEGIN{
+	case 'm':
+		multi = 1;
+		break;
+	case 'n':
+		s = ARGF();
+		if(s){
+			nlines = atoi(s);
+			break;
+		}
+		/* fall through */
+	default:
+		fprint(2, "usage: read [-m] [-n nlines] [files...]\n");
+		exits("usage");
+	}ARGEND
+
+	if(argc == 0)
+		lines(0, "<stdin>");
+	else
+		for(i=0; i<argc; i++){
+			fd = open(argv[i], OREAD);
+			if(fd < 0){
+				fprint(2, "read: can't open %s: %r\n", argv[i]);
+				exits("open");
+			}
+			lines(fd, argv[i]);
+			close(fd);
+		}
+
+	exits(status);
+}