Add line

Makefile

@@ -1,11 +1,14 @@
 all: djl-utils.deb
 
 dist: bin DEBIAN.control
-bin: sign pasta suptime countdown stopwatch timestamp
+bin: line sign pasta suptime countdown stopwatch timestamp
 
 distdir:
 	mkdir -p dist/usr/bin
 
+line: src/line.c distdir
+	cc -o dist/usr/bin/line src/line.c
+
 sign: src/sign distdir
 	cp src/sign dist/usr/bin
 

src/line.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2020 Dylan Lom <djl@dylanlom.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "util/util.h"
+
+const char* argv0;
+
+void usage() {
+    fprintf(stderr, "usage: %s ln\n", argv0);
+    exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[]) {
+    SET_ARGV0();
+
+    if (argc < 1) usage();
+    int ln;
+    char *p;
+    ln = (int)strtol(argv[0], &p, 10);
+    if (errno != 0 || *p != '\0') {
+        fprintf(stderr, "strtol: %s\n", errno
+                ? strerror(errno)
+                : "Failed to parse ln argument."
+        );
+        exit(EXIT_FAILURE);
+    }
+    SHIFT_ARGS();
+
+    int cln = 1;
+    while (cln <= ln) {
+        char c;
+        int r;
+        r = read(STDIN_FILENO, &c, 1);
+        if (r == -1) {
+            fprintf(stderr, "read: %s\n", strerror(errno));
+            exit(1);
+        } else if (r == 0) {
+            exit(2);
+        } else if (cln == ln) {
+            putc(c, stdout);
+        }
+
+        if (c == '\n') cln++;
+    }
+
+    return EXIT_SUCCESS;
+}
+