The MIDAS odbedit utility is primarily an Online Database (ODB) Editor. It also acts as a run control and has limited run monitoring features, so is an alternative to the web-based run control program mhttpd. On the other hand, mhttpd has limited editing capability, and does not support all of the features of odbedit.
The features of odbedit include
- create the ODB of the desired size
- save all or part of the ODB onto disk and reload from a saved file
- list/create/rename/re-order/delete ODB keys
- edit contents of ODB keys
- create (soft)links to ODB keys
- start/stop runs
- list and shutdown active clients
- create a c-structure from the ODB
- change a key's access mode (e.g. read-only)
- execute a list of commands from a file
- connect to corrupted ODB
odbedit treats the hierarchical online database very much like a file system. Most commands are similar to UNIX file commands, e.g. ls, cd, chmod, ln etc. The help command displays a short description of all commands.
The odbedit commands and mode of operation are described fully in the following sections.
Starting odbedit utility
Arguments [ -h hostname ] [ -e exptname ] [-c command ] : Perform a single command. See using an external command [-c @commandFile ] : Perform commands in sequence found in the commandFile. See using an external command file [-s size ] : Size in bytes (for ODB creation). See creating the ODB. [-d ODB Subtree] : Specify the initial entry ODB path to go to. See Specifying the ODB entry path. [-g] : Debug [-C ] : Connect to corrupted ODB Usage >odbedit
Command Line Interpreter
ODBedit has a simple command line interface with command line editing similar to the UNIX tcsh shell. The following edit keys are implemented:
[Backspace] Erase the character left from cursor [Delete/Ctrl-D] Erase the character under cursor [Ctrl-W/Ctrl-U] Erase the current line [Ctrl-K] Erase the line from cursor to end [Left arrow/Ctrl-B] Move cursor left [Right arrow/Ctrl-F] Move cursor right [Home/Ctrl-A] Move cursor to beginning of line [End/Ctrl-E] Move cursor to end of line [Up arrow/Ctrl-P] Recall previous command [Down arrow/Ctrl-N] Recall next command [Ctrl-F] Find most recent command which starts with current line [Tab/Ctrl-I] Complete the path. The command ls /Sy <tab> becomes ls /System.
Creating the ODB
When odbedit is started for the first time, if there is no existing ODB for the experiment (see Common Parameters to MIDAS Utilities #Midas experiment (exptname)) the ODB will be created with the default size of 128KB, unless overruled by the -s <size> argument.
Using an external command
In the simplest case, a single odbedit command can be entered on the command line using the -c argument, e.g.
[pol@isdaq01 src]$ odbedit -c start Starting run #401 Run #401 started [pol@isdaq01 src]$ odbedit -c stop Run #401 stopped
Using an external command file
Perform commands in sequence found in the specified commandFile e.g.
[pol@isdaq01 pol]$ odbedit -d /Equipment/TDC/Settings/ -c @testfile.com
where the file "testfile.com" contains odbedit commands, such as
set testval 4 ls testval start
This external command feature allows for sophisticated shell scripts to be created that can manipulate the odb. Such scripts can for example
- check ODB parameters prior to beginning of run
- send run parameters to the electronic logbook
Scripts using the external command feature are often used at begin and end of run, see also /Programs/execute on start run
Specifying the initial ODB entry path
The odbedit -d argument is used in conjunction with the -c argument to specify the initial path, e.g.
[pol@isdaq01 pol]$ odbedit -d /test -c "set testval 3" [pol@isdaq01 pol]$ odb [local:pol:S]/>ls test testval