inotail.c: Add basic support for +/-<num> to -c/-n

2 files changed, 9 insertions, 2 deletions

diff --git a/inotail.c b/inotail.c
index 1c5f8f0..123a3fa 100644
--- a/inotail.c
+++ b/inotail.c
@@ -328,8 +328,8 @@ int main(int argc, char **argv)
 {
 	int i, c, ret = 0;
 	int n_files = 0;
-	unsigned int n_units = DEFAULT_N_LINES;
-	char forever = 0, mode = M_LINES;
+	int n_units = DEFAULT_N_LINES;
+	char forever = 0, mode = M_LINES, relative = R_END;
 	char **filenames;
 	struct file_struct *files;
 
@@ -339,6 +339,10 @@ int main(int argc, char **argv)
 		case 'n':
 			if (c == 'c')
 				mode = M_BYTES;
+			if (*optarg == '+')
+				relative = R_BEGIN;
+			else if (*optarg == '-')
+				optarg++;
 			n_units = strtoul(optarg, NULL, 0);
 			if (n_units < 0)
 				n_units = 0;
diff --git a/inotail.h b/inotail.h
index b47e6a4..40b0e29 100644
--- a/inotail.h
+++ b/inotail.h
@@ -7,6 +7,9 @@
 /* tail modes */
 enum { M_LINES, M_BYTES };
 
+/* tail unit relative to the end ('-' or none) or the beginning ('+' of the file) */
+enum { R_END, R_BEGIN };
+
 /* Every tailed file is represented as a file_struct */
 struct file_struct {
 	char *name;		/* Name of file (or '-' for stdin) */