DOC: comments about usage

share/fsl/sbin/update_fsl_package

@@ -6,10 +6,6 @@ that have been created with the fslinstaller.py script. It is not intended to
 be used within conda environments that have had FSL packages installed into
 them - in this scenario, conda should be used directly.
 
-Currently this script cannot be used to install new packages - it is limited to
-updating packages that are already installed. To install new packages, conda
-should be used directly.
-
 The script performs the following steps:
 
  1. Parses command line arguments (primarily the list of packages to
@@ -19,6 +15,14 @@ The script performs the following steps:
     the requested packages.
 
  4. Runs "conda install" to update the packages.
+
+This script works on the assumption that the dependencies of FSL package will
+not change - it uses the --no-deps option to the conda install command, so that
+only the requested packages are updated.
+
+Currently this script cannot be used to install new packages - it is limited to
+updating packages that are already installed. To install new packages, conda
+should be used directly.
 """
 # Note: Conda does have a Python API:
 #
@@ -488,8 +492,8 @@ def confirm_installation(packages : Sequence[Package], yes : bool) -> bool:
     packages.
     """
 
-    rows = [('Package name', 'Currently installed', 'Updating to'),
-            ('------------', '-------------------', '-----------')]
+    rows = [('Package name', 'Installed', 'Available'),
+            ('------------', '---------', '---------')]
 
     # Currently all requested packages should already
     # be installed, so a package should never be "n/a".