[PATCH] doc: Improve NUM documentation for head and tail

[Dragan Simic]

Clarify that the NUM values for head and tail are indices, and briefly
describe the specifics of +NUM for tail.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
---
 src/head.c | 3 ++-
 src/tail.c | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/head.c b/src/head.c
index 7bba1420c..e82f9e195 100644
--- a/src/head.c
+++ b/src/head.c
@@ -137,7 +137,8 @@ With more than one FILE, precede each with a header giving 
the file name.\n\
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
       fputs (_("\
 \n\
-NUM may have a multiplier suffix:\n\
+NUM values are indices, thus counting lines and bytes in a file starts\n\
+from one.  NUM may also have a multiplier suffix:\n\
 b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,\n\
 GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y, R, Q.\n\
 Binary prefixes can be used, too: KiB=K, MiB=M, and so on.\n\
diff --git a/src/tail.c b/src/tail.c
index db0913652..4d46498e4 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -313,7 +313,9 @@ With more than one FILE, precede each with a header giving 
the file name.\n\
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      fputs (_("\
 \n\
-NUM may have a multiplier suffix:\n\
+NUM values are indices, thus counting lines and bytes in a file starts\n\
+from one.  This also applies to +NUM, which effectively specifies the line\n\
+or byte index, not the offset.  NUM may also have a multiplier suffix:\n\
 b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,\n\
 GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y, R, Q.\n\
 Binary prefixes can be used, too: KiB=K, MiB=M, and so on.\n\
-- 
2.33.1