Provided by: pcp_4.3.1-1_amd64 bug

NAME

       pmdabash - Bourne-Again SHell trace performance metrics domain agent

SYNOPSIS

       $PCP_PMDAS_DIR/bash/pmdabash  [-C] [-d domain] [-l logfile] [-I interval] [-t timeout] [-U
       username] configfile

DESCRIPTION

       pmdabash is an experimental Performance Metrics Domain Agent (PMDA) which exports "xtrace"
       events  from  a  traced  bash(1) process.  This includes the command execution information
       that would usually be sent to standard error with the set -x option to the shell.

       Event metrics are exported showing each command  executed,  the  function  name  and  line
       number in the script, and a timestamp.  Additionally, the process identifier for the shell
       and its parent process are exported.

       This requires bash version 4 or later.

       A brief description of the pmdabash command line options follows:

       -d   It is absolutely crucial that the performance metrics domain number specified here is
            unique and consistent.  That is, domain should be different for every PMDA on the one
            host, and the same domain number should be used for the same PMDA on all hosts.

       -l   Location of the log file.  By default, a log file named bash.log is  written  in  the
            current  directory  of pmcd(1) when pmdabash is started, i.e.  $PCP_LOG_DIR/pmcd.  If
            the log file cannot be created or is not writable, output is written to the  standard
            error instead.

       -s   Amount  of  time  (in seconds) between subsequent evaluations of the shell trace file
            descriptor(s).  The default is 2 seconds.

       -m   Maximum amount of memory to be allowed for each event queue (one per traced process).
            The default is 2 megabytes.

       -U   User  account  under  which  to run the agent.  The default is the unprivileged "pcp"
            account in current versions of PCP, but  in  older  versions  the  superuser  account
            ("root") was used by default.

INSTALLATION

       In  order  for  a  host to export the names, help text and values for the bash performance
       metrics, do the following as root:

            # cd $PCP_PMDAS_DIR/bash
            # ./Install

       As soon as an instrumented shell script (see INSTRUMENTATION selection below) is run, with
       tracing  enabled,  new  metric  values  will  appear  -  no  further setup of the agent is
       required.

       If you want to undo the installation, do the following as root:

            # cd $PCP_PMDAS_DIR/bash
            # ./Remove

       pmdabash is launched by pmcd(1) and should never be executed directly.   The  Install  and
       Remove scripts notify pmcd(1) when the agent is installed or removed.

INSTRUMENTATION

       In order to allow the flow of event data between a bash(1) script and pmdabash, the script
       should take the following actions:

            #!/bin/sh
            source $PCP_DIR/etc/pcp.env
            source $PCP_SHARE_DIR/lib/bashproc.sh

            pcp_trace on $@       # enable tracing
            echo "awoke, $count"

            pcp_trace off         # disable tracing

       The tracing can be enabled and disabled any number of times by the script.  On  successful
       installation of the agent, several metrics will be available:

            $ pminfo bash
            bash.xtrace.numclients
            bash.xtrace.maxmem
            bash.xtrace.queuemem
            bash.xtrace.count
            bash.xtrace.records
            bash.xtrace.parameters.pid
            bash.xtrace.parameters.parent
            bash.xtrace.parameters.lineno
            bash.xtrace.parameters.function
            bash.xtrace.parameters.command

       When  an  instrumented  script is running, the generation of event records can be verified
       using the pmevent(1) command, as follows:

            $ pmevent -t 1 -x '' bash.xtrace.records
            host:      localhost
            samples:   all
            bash.xtrace.records["4538 ./test-trace.sh 1 2 3"]: 5 event records
              10:00:05.000 --- event record [0] flags 0x19 (point,id,parent) ---
                bash.xtrace.parameters.pid 4538
                bash.xtrace.parameters.parent 4432
                bash.xtrace.parameters.lineno 43
                bash.xtrace.parameters.command "true"
              10:00:05.000 --- event record [1] flags 0x19 (point,id,parent) ---
                bash.xtrace.parameters.pid 4538
                bash.xtrace.parameters.parent 4432
                bash.xtrace.parameters.lineno 45
                bash.xtrace.parameters.command "((  count++  ))"
              10:00:05.000 --- event record [2] flags 0x19 (point,id,parent) ---
                bash.xtrace.parameters.pid 4538
                bash.xtrace.parameters.parent 4432
                bash.xtrace.parameters.lineno 46
                bash.xtrace.parameters.command "echo 'awoke, 3'"
              10:00:05.000 --- event record [3] flags 0x19 (point,id,parent) ---
                bash.xtrace.parameters.pid 4538
                bash.xtrace.parameters.parent 4432
                bash.xtrace.parameters.lineno 47
                bash.xtrace.parameters.command "tired 2"
              10:00:05.000 --- event record [4] flags 0x19 (point,id,parent) ---
                bash.xtrace.parameters.pid 4538
                bash.xtrace.parameters.parent 4432
                bash.xtrace.parameters.lineno 38
                bash.xtrace.parameters.function "tired"
                bash.xtrace.parameters.command "sleep 2"

FILES

       $PCP_PMCDCONF_PATH
                 command line options used to launch pmdabash
       $PCP_PMDAS_DIR/bash/help
                 default help text file for the bash metrics
       $PCP_PMDAS_DIR/bash/Install
                 installation script for the pmdabash agent
       $PCP_PMDAS_DIR/bash/Remove
                 undo installation script for pmdabash
       $PCP_LOG_DIR/pmcd/bash.log
                 default log file for error messages and other information from pmdabash

PCP ENVIRONMENT

       Environment variables with the prefix PCP_ are used to parameterize the file and directory
       names used by PCP.  On each installation, the file /etc/pcp.conf contains the local values
       for these variables.  The $PCP_CONF  variable  may  be  used  to  specify  an  alternative
       configuration file, as described in pcp.conf(5).

SEE ALSO

       bash(1), pmevent(1) and pmcd(1).