Add showcolors.bash

.gitignore

@@ -6,4 +6,5 @@
 !README.md
 !doc/signify.txt
 !plugin/signify.vim
+!showcolors.bash
 !signify.gif

doc/signify.txt

@@ -264,9 +264,9 @@ Personally I use (256 colors terminal):
     highlight SignifySignDelete cterm=bold ctermbg=237  ctermfg=167
     highlight SignifySignChange cterm=bold ctermbg=237  ctermfg=227
 
-For Unix people there is a small script, showcolors.sh, in the repo that shows
-all 256 colors available to the terminal. That makes picking the right numbers
-much easier.
+For Unix people there is a small script, showcolors.bash, in the repo that
+shows all 256 colors available to the terminal. That makes picking the right
+numbers much easier.
 
 
 ==============================================================================

showcolors.bash

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+if ! hash tput 2>/dev/null; then
+    echo "I cannot find the 'tput' program." \
+        'You might find it in one of the ncurses packages.' >&2
+    exit 1
+fi
+
+for i in {0..255}; do
+    tput setab $i && echo -n " $i "
+done