Add some documentation

1 files changed, 12 insertions, 1 deletions

diff --git a/el.c b/el.c
index 518b3a7..87dd7fb 100644
--- a/el.c
+++ b/el.c
@@ -58,7 +58,8 @@ static int nextchar( void ) {
     return getchar();
   if( *g_immediatelinenums )
     return *g_immediatelinenums++;
-  return EOF;
+  g_immediatelinenums = 0;
+  return ' ';
 }
 
 // scans the text file for the requested line
@@ -172,6 +173,16 @@ static int acquire_lineno( int c ) {
 
 static void usage() {
   fputs( "Usage: el [-0Ggnxh] [-i linenums] filename .. < linenum_file\n", stderr);
+
+  fputs( "    -i  Use <linenums> before (or instead) using line numbers from stdin\n", stderr );
+  fputs( "    -0  Line numbers are zero base\n", stderr );
+  fputs( "    -x  Line numbers default to base 16\n", stderr );
+  fputs( "    -g  Line numbers are followed by colon (as grep -n produces)\n", stderr );
+  fputs( "    -G  Like -g but also prepend output line by input line\n", stderr );
+  fputs( "    -n  Prepend output by line number and colon (like grep -n)\n", stderr );
+  fputs( "    -h  Print this help\n", stderr );
+  fputs( "\nExample: grep -n Foo File1 | el -Gn File2 File3 | grep Bar | el -Gn File4\n", stderr );
+
 }
 
 int main( int argc, char **argv ) {