cdb: database fron environment by default

diff --git a/README.rst b/README.rst
index f031933310ab815c5012065912f9ff4dde6af6df..afb18cb8d1a135d0860e0eade8981d26ca4d4116 100644 (file)
--- a/README.rst
+++ b/README.rst
@@ -33,12 +33,17 @@ This program requires...
 Supported Operations
 ####################
 
+To reduce clutter, many of the examples here rely on ``cdb``'s ability to pull
+the default database from the ``$CDB`` environment variable.  If that's not what
+you want, add ``--db ${DB}`` to the invocation of ``cdb``.
+
+
 Initialize A Database
 =====================
 
 ::
 
-   cdb --db ${DB} init
+   cdb init
 
 Observe A Path
 ==============
@@ -46,17 +51,17 @@ Observe A Path
 Add the checksum of a single path to the database.  This will create a new
 checksum and/or a new path identifier as needed and will bind them together. ::
 
-   sha512sum $FILE | cdb --db ${DB} addh
+   sha512sum $FILE | cdb addh
 
 Or, for all files under a path::
 
-   find $DIR -type f -exec sha512sum {} \+ | cdb --db ${DB} addh
+   find $DIR -type f -exec sha512sum {} \+ | cdb addh
 
 If we have a pile of digest files already, each of which contains digests of
 paths relative to its location, we can generate a database, ``${DB2}`` from them
 with the assistance of the ``cdb-util digest-relativize`` tool::
 
-  find ${DIR} -type f -name SHA512SUMS -print0 | cdb-util drel --inul | cdb --db ${DB} addh
+  find ${DIR} -type f -name SHA512SUMS -print0 | cdb-util drel -1 | cdb addh
 
 Revalidate A Path Observation
 =============================
@@ -64,23 +69,23 @@ Revalidate A Path Observation
 Measure the checksum of a path and confirm that the database already held that
 observation.  Reports unexpected files as well as mis-checksummed contents. ::
 
-   sha512sum $FILE | cdb --db ${DB} verh
+   sha512sum $FILE | cdb verh
 
 Or for all files under a path::
 
-   find $DIR -type f -exec sha512sum {} \; | cdb --db ${DB} verh
+   find $DIR -type f -exec sha512sum {} \; | cdb verh
 
 This processing of digest streams is to be preferred to verifying a digest
 stream as generated by the database, e.g.::
 
-   cdb --db ${DB} look \* | sha512sum -c
+   cdb look \* | sha512sum -c
 
 because the former can be more informative in the case of mismatching digests
 (specifically, the database can look for other paths that have the reported
 digest).  If it's easier to have the database generate the set of files, that
 can be done::
 
-   cdb --db ${DB} look \* --format '$u$z' --nul | xargs -0 sha512sum | cdb --db ${DB} verh
+   cdb look \* --format '$u$z' --nul | xargs -0 sha512sum | cdb verh
 
 Add Missing Checksums
 =====================
@@ -105,7 +110,7 @@ We can then script computing those files' checksums and adding the new reports
 to the database::
 
    xargs -0 sha512sum > ${DB}.new < ${DB}.new-files0
-   cdb --db ${DB} addh < ${DB}.new
+   cdb addh < ${DB}.new
 
 Using diff
 ----------
@@ -178,7 +183,7 @@ By Existing Paths
 Indicate that some file contents are to be considered a lesser version of some
 other contents::
 
-   cdb --db ${DB} addsuper /old/path /new/path
+   cdb addsuper /old/path /new/path
 
 After this command is run, ``domv`` will be willing to remove the ``/old/path``
 entry from the database.
@@ -205,7 +210,7 @@ to import into the library.  Novel hashes, and their new paths, may optionally
 be recorded as well, to be subsequently added to the database::
 
   find /source/path -type f -exec sha512sum {} \+ | \
-    cdb --db ${DB} ingest --target /new/path --prune
+    cdb ingest --target /new/path --prune
 
 This will produce a stream of shell commands to copy files given by ``find``
 into the ``/new/path`` directory (using their basename therein).  Passing
@@ -242,11 +247,11 @@ above::
 
 We can then prepare to prune duplicates and add unique files::
 
-   cdb --db ${DB} ingest --prune --inplace --digest-log ${DB}.new2 < ${DB}.new > ${DB}.prune
+   cdb ingest --prune --inplace --digest-log ${DB}.new2 < ${DB}.new > ${DB}.prune
 
 Add new files to the database with::
 
-   cdb --db ${DB} addh < ${DB}.new2
+   cdb addh < ${DB}.new2
 
 Inspect the pruning commands to be run, and then execute them with::
 

diff --git a/cdb b/cdb
index a791c690b5a4c16a7ed46c12d1cd018efe4a0351..5dad4454efc992449e4ee3a86b09ac3bbc555528 100755 (executable)
--- a/cdb
+++ b/cdb
@@ -190,7 +190,8 @@ local argp = argparse("cdb", "checksum database tool")
 argp:option("--db --database")
   :target("database")
   :args(1)
-  :description("Indicate primary checksum database")
+  :default(os.getenv("CDB"))
+  :description("Indicate primary checksum database (or use $CDB)")
 
 -- grouping logic, part 1.  Sadly, this needs to run "all at once" but we want
 -- to define our commands incrementally!