In Python, What Are Some Disadvantages to Using os.execlp to Fork a Process?

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Question
In Python you are familiar with importing the os module and using different exec variations. What are some reasons that you would not use os.execlp?

Answer
1. If you use os.execlp to call another program, that program is more likely to return “Killed”. The resources of the child process are, by default, more limited in part because the fork operation is expensive from a system’s resources perspective.

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How Do You Install Java so You Can Compile Programs on a RHEL Server?

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Problem scenario
You have installed Java. But you cannot use the javac command. You get errors like this: “-bash: javac: command not found”

How do you install Java so you can compile programs on a RedHat Linux server?

Solution
Run this command: sudo yum -y install java-devel

If you want to do this on a Debian or Ubuntu Linux server,

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How Do You Pass Parameters to a Function in Golang and Assign the Returned Value to a Variable?

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Problem scenario
You want to pass parameters to a function and assign the returned value to a parameter using the Go programming language. What should you do?

Solution
Prerequisite
This assumes that you have installed Golang; if you need assistance with this, see this posting.

Procedures
1.

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How Do You Get Python to Compute How Long Something Took?

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Problem scenario
You want to check the runtime duration of a section of Python code. How do you compute the amount of time something took in Python?

Solution
Write a program like this:

import datetime, time
t1 = datetime.datetime.now()
time.sleep(5) # replace this line with the section of code you want to time
t2 = datetime.datetime.now()
t3 = t2 – t1
print(“Time format is in hours:minutes:seconds:seconds_decimals”)
print(t3) …

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How Do You Troubleshoot the Go Programming Error ‘non-name m1[“foo”] on left side of :=’?

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Problem scenario
You are running a Go program. You see this message about “command-line-arguments”:

non-name m1[“foo”] on left side of :=

What should you do?

Possible Solution
Can you try to use “=” instead of “:=”? This may fix your problem.

The := is a variable declaration and an assignment. If your map has been declared,

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How Do You Use a Function in Golang?

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Problem scenario
You are trying to learn to program in Go. How do you use a function?

Solution
Prerequisite
This assumes that you have installed Golang; if you need assistance with this, see this posting.

Procedures
1. Create a file called b.go with this as the content:

package main

import “fmt”

// ContintFunction will display a message
func ContintFunction() {
fmt.Println(“Hello from Continual Integration”)
}

func main() {
ContintFunction()
}

2.

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In Python, How Do You Call a Bound Function as a New Thread with the thread Module?

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Problem scenario
You want to write a program to call a bound function in a new thread. How do you do this?

Solution
Run this program (e.g., python foobar.py):

import _thread as thread
class mighty:
def cool():
print(“Cool.”)
def contint():
print(“Hello!”)
if name == “main”:
foobar = thread.start_new_thread(mighty.cool, () )
print(“thread finished…exiting”)

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How Do You Create a List of Strings in Golang?

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Problem scenario
Lists have a fixed length number of discrete items. You want the items in the list to be strings. How do you create a list of strings in Golang?

Solution
1. Use this program called animal.go:

package main

import “fmt”

func main() {
var x [10]string
x[0] = “dog”
x[1] = “cat”
x[2] = “hamster”
x[3] = “rabbit”
x[4] = “chicken”

for i := 0; …

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How Do You Create Your Own RPM Package (Binary File) for Your Own C Program?

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Problem scenario
You want to know more about RPM packaging so you can create your own .rpm file (a custom RPM package file).  In other words you want to create your own RPM package (a binary file).  You want it for installing an uncompiled C program you wrote.  The uncompiled C program is one .c file and very simple.  You don’t know how to use a spec (specification) file to create your own RPM package file. 

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