9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
So I'm trying to pass certain json elements as env vars and use them later on in a script.
Sample json:
JSON='{
"Element1": "file-123456",
"Element2": "Name, of, company written in, a very weird way",
"Element3": "path/to/some/file.txt",
}'
(part of the) script:
for s... (5 Replies)
Discussion started by: da1
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2. Shell Programming and Scripting
I realise this is not entirely a shell question because it involves the C language but it centers around a Bash script I have written.
I have written a couple of bash script files that communicate via two serial ports. One script can be thought of as a receiver and the other as a transmitter.... (3 Replies)
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3. UNIX for Advanced & Expert Users
Good Morning
I think there may be something I dont understand fully.
The following code works well, but I dont like the set domen method.
#!/bin/bash
#
domen="y"
while
do
echo " M A I N - M E N U"
echo "1. Contents of /etc/passwd"
echo "2. List of users currently logged"
echo... (10 Replies)
Discussion started by: popeye
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4. UNIX for Advanced & Expert Users
I am trying to get my history in sync in multiple bash sections and things aren't working the way I expect.
Desired behavior, hitting esc-K in all bash sessions (same userid and machine) will use the same history.
Observed behavior: Esc-k shows the history of the current session, rather than... (8 Replies)
Discussion started by: gg48gg
8 Replies
5. Shell Programming and Scripting
Moderators,
Please excuse if I am in the wrong section.
I have a question that someone may know the answer to. We know that a current bash shell keeps a record of all commands in a buffer. When the shell is terminated this buffer is written out to ~/.bash_history for the user.
I know... (2 Replies)
Discussion started by: jaysunn
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6. UNIX for Advanced & Expert Users
run_xfs_fsr is a xfs filesystem maintenance script designed to run under cron. The system is a home theater personal computer running mythbuntu 10.10, and is accessed remotely for these tests. cron runs a script, (xfs_fsr.sh) at 02:30 that runs the subject script under BASH and sets the... (3 Replies)
Discussion started by: keepitsimpleeng
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7. Red Hat
Hi all
I am relatively new to linux (specifically red hat). I have installed Fedora 13 on my machine and started playing with the terminal when i found a very strange behavior when typing a command that is not found:
the terminal does not prompt me back. In other words, i am logged as root (or... (4 Replies)
Discussion started by: abohmeed
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8. UNIX for Dummies Questions & Answers
Is it possible to use the keyboard UP ARROW in place of k to recall history? If so, how/what do I need to do change terminal emulation, etc.?
TIA,
George (7 Replies)
Discussion started by: gwfay
7 Replies
9. Shell Programming and Scripting
The block below isn't a surprise:$ ls
file1 file2 file3
$ x=*
$ echo $x
file1 file2 file3
$ echo '$x'
$x
$ echo "$x"
*
$But I found this block a bit bewildering:$ echo $x'
>'
*
$I'm wondering why substitution wasn't performed on the $x, since it was unquoted (as far as I can tell).... (5 Replies)
Discussion started by: na5m
5 Replies
PMDABASH(1) General Commands Manual PMDABASH(1)
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.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 configura-
tion file, as described in pcp.conf(5).
SEE ALSO
bash(1), pmevent(1) and pmcd(1).
Performance Co-Pilot PCP PMDABASH(1)