pickrand.py: allow selecting from a set of files

Allow selecting from a set of files specified on the command line,
rather than just all files in the current directory tree.

Signed-off-by: Colin McCabe <cmccabe@alumni.cmu.edu>

diff --git a/pickrand.py b/pickrand.py
index 6340971..688460a 100755 (executable)
--- a/pickrand.py
+++ b/pickrand.py
@@ -3,26 +3,29 @@
 import os
 import random
 import sys
+import time
 
 print_to_stderr = False
+random.seed(os.getpid() + int(time.time()))
+
+file_name = None
 if (len(sys.argv) == 1):
-    pass
+    allfiles = []
+    for root, dirs, files in os.walk("."):
+        for f in files:
+            allfiles.append(os.path.join(root, f))
+    if (len(allfiles) == 0):
+       sys.exit(1)
+    r = random.randint(0,len(allfiles) - 1)
+    file_name = allfiles[r]
 elif (len(sys.argv) == 2) and (sys.argv[1] == "-S"):
     print_to_stderr = True
 else:
-    print >>sys.stderr, "invalid command-line arguments"
-    sys.exit(1)
-
-allfiles = []
+    allfiles = sys.argv[1:]
+    r = random.randint(0,len(allfiles) - 1)
+    file_name = allfiles[r]
 
-for root, dirs, files in os.walk("."):
-    for f in files:
-        allfiles.append(os.path.join(root, f))
-if (len(allfiles) == 0):
-   sys.exit(1)
-random.seed(os.getpid())
-r = random.randint(0,len(allfiles) - 1)
-print(allfiles[r])
+print(file_name)
 if (print_to_stderr):
-    print >>sys.stderr, (allfiles[r])
+    print >>sys.stderr, file_name
 sys.exit(0)