doc: clarify when seq ends

* doc/coreutils.texi (seq invocation): Add a sentence clarifying
that seq terminates when LAST becomes smaller than the current number
plus INCREMENT.
* src/seq.c (usage): Likewise.
Fixes http://bugs.gnu.org/15068

1 files changed, 2 insertions, 0 deletions

diff --git a/src/seq.c b/src/seq.c
index acbe2350a..35dfc8bd0 100644
--- a/src/seq.c
+++ b/src/seq.c
@@ -87,6 +87,8 @@ Print numbers from FIRST to LAST, in steps of INCREMENT.\n\
 \n\
 If FIRST or INCREMENT is omitted, it defaults to 1.  That is, an\n\
 omitted INCREMENT defaults to 1 even when LAST is smaller than FIRST.\n\
+The sequence of numbers ends when the sum of the current number and\n\
+INCREMENT would become greater than LAST.\n\
 FIRST, INCREMENT, and LAST are interpreted as floating point values.\n\
 INCREMENT is usually positive if FIRST is smaller than LAST, and\n\
 INCREMENT is usually negative if FIRST is greater than LAST.\n\