OK, some "theory of programming 101" seems to be in order.
Thanks for you effort to help me. I'm not a programmer, but a senior system administrator with experience in a dozen different scripting languages and some mainly school-only experience with C/C++/Java. I read your thread in full but did not discover any additional knowledge, which I do not already have. But again, thanks for your kindness to write such extensive explanations for me.
Quote:
pattern is a filename matching pattern; not a regular expression. To get rid of the last || followed by any string of characters from the end of the variable var , you just need:
Code:
Of course that is correct. I wrote ${out%||[0-9]*}, because I wanted a numerical value(Exit code) to be matched. That is not meant as a regex. Since it never should be zero chars long, which would be the meaning of the regex. It should be a number followed by something.
The reason was because of the not very likely case, the program output contains ||. I'm realizing now that this is not possible, because ${..%||*} matches only the last occurrance of the the pattern, which must be the one I appended myself. So my construction does not add any extra value.
Quote:
But, I have no idea why that is something you would want to do??? And, if that is something you want to do, that is not the way to do it.
Setting OUT to the string "<EMPTY>" is exactly what I'm accomplishing here. The reason is to explicitly point out in the logfile that the command did not output any result. I want it that way because it's a clearer message than just an empty string, which may have other reasons to occur.
---
Thanks for all hints so far. Any hints on the main question asked? ...which is: Ideas and hints to getting nicer, more easy to use/read bash-code on the calling side outside of the _exec function.
OpenBSD complains when it sees this function in my program
/*This function takes the string "test\n" and returns the string "test\n\test\ntest\n"
ENTROPY = 1024
*/
void *build_string(int count, char **strarr)
{
int k;
char *new;;
size_t max;
if(count == 0) {
... (2 Replies)
hi
how can I return multiple values from a C function. I tried the following:
#include <stdio.h>
void foo(int id, char *first_name, char *last_name)
{
/*
this is just an example to illustrate my problem... real code makes
use of the "id" parameter.
*/
first_name = (char... (8 Replies)
Hi,
I have a script which does something like the below:
execute_some_script.sh $arg1 $arg2 `exec-some-cmd`
if then;
do something
else
do something else
fi
However, during some cases, there is an error saying:
line xxx: [: too many arguments
at the line number which has... (5 Replies)
Hi there, I have the following output,
# raidctl -l
RAID Volume RAID RAID Disk
Volume Type Status Disk Status
------------------------------------------------------
c0t1d0 IM OK c0t1d0 OK
... (4 Replies)
Hi,
I need to retrun multiple values
function errorFileCreation
{
echo "Before"
return -1 "Siva";
echo "Aftyer"
}
echo ${?} - This can be used to getting first value.
how can i get second one.
Advance Thanks...
Shiv (3 Replies)
I know multiple values can be returned from a function in C like this:
char **read_file ( char * , unsigned long int * );//this is the function prototypeunsigned long int number_of_words = 0;//variable defined in main() and initialized to 0words_from_dictionary = read_file ( "dictionary.dit" ,... (2 Replies)
Hello,
i'm trying to implement the times() function and i'm programming in C.
I'm using the "struct tms" structure which consists of the fields:
The tms_utime structure member is the CPU time charged for the execution of user instructions of the calling process.
The tms_stime structure... (1 Reply)
Hello!
I have one strange question - let's say I have a long, multiple-line string displayed on the terminal using echo, and I would like to make a carriage return to the beginning of this string, no to the beginning of the last line - is something like that possible? I would like to be able to... (1 Reply)
I am using a for loop to copy files from say DIR1 and DIR2 to DIR3.I have to check whether files are copied from DIR1 and DIR2 and print the respective message.
@path=("$DIR1","$DIR2");
foreach (@path) {
$rc=system("cp $_/*xml $DIR3");
if ($rc == 0)
{
print "Files were copied... (1 Reply)
Hi
I am pretty confused in returning and capturing multiple values
i have defined a function which should return values "total, difference"
i have used as
#!/usr/bin/ksh
calc()
{
total=$1+$2
echo "$total"
diff=$2-$1
echo "$diff"
}
I have invoked this function as
calc 5 8
Now i... (2 Replies)
Discussion started by: Priya Amaresh
2 Replies
LEARN ABOUT CENTOS
pmdabash
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)