diff --git a/diversity.cabal b/diversity.cabal
--- a/diversity.cabal
+++ b/diversity.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                diversity
-version:             0.3.5.0
+version:             0.3.5.1
 synopsis:            Return the diversity at each position for all sequences in a fasta file
 description:         Find the diversity of a collection of entities, mainly for use with fasta sequences. Produces a binary which works on fasta files to find the diversity of any order and rarefaction curves for a sliding window across all positions in the sequences. To analyze just a collection of entities, just use the whole sequences and list flag.
 homepage:            https://github.com/GregorySchwartz/diversity
diff --git a/src/src-exec/Main.hs b/src/src-exec/Main.hs
--- a/src/src-exec/Main.hs
+++ b/src/src-exec/Main.hs
@@ -119,19 +119,22 @@
          <> value ""
          <> help "The csv file containing the rarefaction values (the percent\
                  \ of the rarefaction curve that is above 95% of the height of\
-                 \ the rarefaction curve)" )
+                 \ the rarefaction curve). Expects a string, so you need a\
+                 \ string even with std" )
       <*> strOption
           ( long "output-rarefaction-curve"
          <> short 'c'
          <> metavar "FILE"
          <> value ""
-         <> help "The csv file containing the rarefaction curve" )
+         <> help "The csv file containing the rarefaction curve. Expects a\
+                 \ a string, so you need a string even with std" )
       <*> strOption
           ( long "output"
          <> short 'o'
          <> metavar "FILE"
          <> value ""
-         <> help "The csv file containing the diversities at each position" )
+         <> help "The csv file containing the diversities at each position.\
+                 \ expects a string, so you need a string wven with std" )
 
 generateDiversity :: Options -> IO ()
 generateDiversity opts = do