Add command-line option to sort object keys.

Closes #79.

2 files changed, 10 insertions, 2 deletions

diff --git a/docs/content/3.manual/manual.yml b/docs/content/3.manual/manual.yml
index df3c177e..7272c880 100644
--- a/docs/content/3.manual/manual.yml
+++ b/docs/content/3.manual/manual.yml
@@ -113,7 +113,11 @@ sections:
         "\u03bc"). Using this option, you can force jq to produce pure
         ASCII output with every non-ASCII character replaced with the
         equivalent escape sequence.
-  
+
+      * `--sort-keys` / `-S`:
+        
+        Output the fields of each object with the keys in sorted order.
+
       * `--raw-output` / `-r`:
   
         With this option, if the filter's result is a string then it
diff --git a/main.c b/main.c
index 822bc6ce..6d11f01d 100644
--- a/main.c
+++ b/main.c
@@ -56,8 +56,9 @@ enum {
   ASCII_OUTPUT = 32,
   COLOUR_OUTPUT = 64,
   NO_COLOUR_OUTPUT = 128,
+  SORTED_OUTPUT = 256,
 
-  FROM_FILE = 256,
+  FROM_FILE = 512,
 
   /* debugging only */
   DUMP_DISASM = 2048,
@@ -82,6 +83,7 @@ static void process(jv value, int flags) {
 #else
       dumpopts = isatty(fileno(stdout)) ? JV_PRINT_COLOUR : 0;
 #endif
+      if (options & SORTED_OUTPUT) dumpopts |= JV_PRINT_SORTED;
       if (!(options & COMPACT_OUTPUT)) dumpopts |= JV_PRINT_PRETTY;
       if (options & ASCII_OUTPUT) dumpopts |= JV_PRINT_ASCII;
       if (options & COLOUR_OUTPUT) dumpopts |= JV_PRINT_COLOUR;
@@ -197,6 +199,8 @@ int main(int argc, char* argv[]) {
       options |= NO_COLOUR_OUTPUT;
     } else if (isoption(argv[i], 'a', "ascii-output")) {
       options |= ASCII_OUTPUT;
+    } else if (isoption(argv[i], 'S', "sort-keys")) {
+      options |= SORTED_OUTPUT;
     } else if (isoption(argv[i], 'R', "raw-input")) {
       options |= RAW_INPUT;
     } else if (isoption(argv[i], 'n', "null-input")) {