1 files changed, 35 insertions, 0 deletions

diff --git a/coreutils/expr.c b/coreutils/expr.c
index 04d783f2b..24e75b556 100644
--- a/coreutils/expr.c
+++ b/coreutils/expr.c
@@ -25,6 +25,41 @@
 
 /* no getopt needed */
 
+//usage:#define expr_trivial_usage
+//usage:       "EXPRESSION"
+//usage:#define expr_full_usage "\n\n"
+//usage:       "Print the value of EXPRESSION to stdout\n"
+//usage:    "\n"
+//usage:       "EXPRESSION may be:\n"
+//usage:       "        ARG1 | ARG2     ARG1 if it is neither null nor 0, otherwise ARG2\n"
+//usage:       "        ARG1 & ARG2     ARG1 if neither argument is null or 0, otherwise 0\n"
+//usage:       "        ARG1 < ARG2     1 if ARG1 is less than ARG2, else 0. Similarly:\n"
+//usage:       "        ARG1 <= ARG2\n"
+//usage:       "        ARG1 = ARG2\n"
+//usage:       "        ARG1 != ARG2\n"
+//usage:       "        ARG1 >= ARG2\n"
+//usage:       "        ARG1 > ARG2\n"
+//usage:       "        ARG1 + ARG2     Sum of ARG1 and ARG2. Similarly:\n"
+//usage:       "        ARG1 - ARG2\n"
+//usage:       "        ARG1 * ARG2\n"
+//usage:       "        ARG1 / ARG2\n"
+//usage:       "        ARG1 % ARG2\n"
+//usage:       "        STRING : REGEXP         Anchored pattern match of REGEXP in STRING\n"
+//usage:       "        match STRING REGEXP     Same as STRING : REGEXP\n"
+//usage:       "        substr STRING POS LENGTH Substring of STRING, POS counted from 1\n"
+//usage:       "        index STRING CHARS      Index in STRING where any CHARS is found, or 0\n"
+//usage:       "        length STRING           Length of STRING\n"
+//usage:       "        quote TOKEN             Interpret TOKEN as a string, even if\n"
+//usage:       "                                it is a keyword like 'match' or an\n"
+//usage:       "                                operator like '/'\n"
+//usage:       "        (EXPRESSION)            Value of EXPRESSION\n"
+//usage:       "\n"
+//usage:       "Beware that many operators need to be escaped or quoted for shells.\n"
+//usage:       "Comparisons are arithmetic if both ARGs are numbers, else\n"
+//usage:       "lexicographical. Pattern matches return the string matched between\n"
+//usage:       "\\( and \\) or null; if \\( and \\) are not used, they return the number\n"
+//usage:       "of characters matched or 0."
+
 #include "libbb.h"
 #include "xregex.h"