add --no-color option to is

This allow displaying to be done without coloration

bin/is

@@ -14,6 +14,7 @@ import re
 import fnmatch
 import warnings
 import installsystems
+import installsystems.printer
 import installsystems.tools as istools
 import installsystems.argparse as argparse # to be removed when python2.7
 from installsystems.printer import *
@@ -318,6 +319,8 @@ p_main.add_argument("-C", "--cache", default=None,
                     help="path of the repository cache")
 p_main.add_argument("--no-cache", action="store_true", default=False,
                     help="not use persistent db caching")
+p_main.add_argument("--no-color", action="store_true", default=False,
+                    help="dot not display colored output")
 p_main.add_argument("-t", "--timeout", dest="timeout", type=int, default=3,
                     help="download timeout (default 3)")
 
@@ -499,6 +502,9 @@ try:
     # no warning if we are not in debug mode
     if not installsystems.debug:
         warnings.filterwarnings("ignore")
+    # disable coloring if asked
+    if args.no_color:
+        installsystems.printer.NOCOLOR = True
     # except for install command we parse all args!
     if args.func is not c_install:
         args = p_main.parse_args(namespace=args)

installsystems/printer.py

@@ -10,7 +10,9 @@ import sys
 import os
 import installsystems
 
-color = {
+NOCOLOR = False
+
+COLOR = {
     # regular
     "black": "\033[30m",
     "B": "\033[30m",
@@ -46,11 +48,11 @@ def out(message="", fd=sys.stdout, endl=os.linesep, flush=True):
     Print message colorised in fd ended by endl
     '''
     # color subsitution
-    for c in color:
-        if fd.isatty():
-            message = message.replace("#%s#" % c, color[c])
-        else:
+    for c in COLOR:
+        if not fd.isatty() or NOCOLOR:
             message = message.replace("#%s#" % c, "")
+        else:
+            message = message.replace("#%s#" % c, COLOR[c])
     # convert unicode into str before write
     # this can cause issue on python 2.6
     if type(message) == unicode:

samples/installsystems.conf

@@ -14,6 +14,9 @@
 # disable cache of remote repository
 #no_cache = 1
 
+# disable output coloring
+#no_color = 1
+
 # disable check of script during build
 #no_check = 1