Principal Software Engineer/Architect, motorcyclist, drummer, and artist
There are times, mostly for logging and debugging, when you have a slice of a given type that you would like to print to a log file or just convert to a CSV of values.
A quick and easy way to convert a slice to a CSV in Golang is to use the json module to Marshal it a JSON encoded array.
package main
import (
"encoding/json"
"fmt"
)
func main() {
ints := []int64{1, 2, 3, If you would like to join an array of elements with a defined delimiter in Bash there is an easy way to go about it by using printf. Following is an example
#!/bin/bash
declare -a arr=()
for i in `seq 1 5`
do
arr=("${arr[@]}" $i)
done
# Generate a single string joined by a comma. The printf string can contain
# any arbitrary delimiter.
printf -v joined '%s,' "${arr[@]}"
# Print out the string minus the trailing comma
echo Sometimes you are making changes to a dependency in another of your go projects and instead of adding a replace command in the go.mod file you want to update that entry in go.mod to point to a specific commit in the repo.
To do so, all that you need to do is:
go.mod file resides in which you want to One of the key features in go is simplicity. As a result there are a number of utilities and data structures that are common in other high-level languages that do not come with the go stdlib.
One of them is a stack. Following is a very simple implementation of a stack that uses a slice to store the data.
The following is an implementation of a simple stack that takes any kind of pointer.
import "fmt"
type Stack[T any] struct The GNU diff command on most Linux and UNIX systems will diff the contents of two files. With Bash, you can, using process substitution, take the output of any arbitrary command and process its input, or output, as a file descriptor. In this way, you can then use diff against the output of two commands as follows
diff <(cmd1) <(cmd2)Both cmd1 and cmd2 will appear as a file name/file descriptor. The < character indicates that the file descriptor should → Continue reading “Diffing the output of two commands”
If you want to dynamically define and export variable names in Bash here is the TLDR;
# Define the name of the variable
key="my-dynamic-var-name"
# Declare it and export it
declare -gx "$key"="some-value"To then access that value via a dynamically generated variable name
# Create a variable that contains the variable name
var_to_access="my-dynamic-var-name"
# Read the value
my_var_value=${!var_to_access}Read the man page for declare for more details and read this article for a really good explanation and further examples.→ Continue reading “Declaring, Exporting, and Reading Dynamic Variables in Bash”
Sometimes you will want to ensure that a file is sourced instead of executed. This ensures, among other things, that any environment variables that the script defines remain in your current shell after the script completes.
To do so, use the following to check whether the file was sourced or run in a sub-shell
(return 0 2/dev/null) && sourced=1 || sourced=0
echo "sourced=$sourced"Bash allows return statements only from functions and in a scripts top level scope IF it → Continue reading “How to check if a file is sourced in Bash”
I have no idea why, but for some reason I always have a hard time remembering the exact syntax for find when I want to prune some list of directories from a search.
Let’s say that you want to execute a find in a directory where there are a lot of .git directories and you don’t want to search through the guts of the repo directories. With the following command we specify the prune predicate ahead of the search for → Continue reading “Pruning directories from find”
The TLDR; is to first use tr to replace all occurrences of any horizontal whitespace character with a single space, and then squeeze down any number of spaces to a single space and then define the delimiter for cut as a single space. The following example assumes that you want to see from the 5th column to the end of the line.
<do-something-to-generate-input| tr '[:blank:]' ' ' | tr -s ' ' | cut -d ' ' -f5-The → Continue reading “Using cut with a delimiter of any amount of whitespace”
I finally was able to get Visual Studio Code set-up correctly to run and debug unit and integration tests for a Python 3.8 project that I am working on (I’ll add a link to that post here once it is up).
After making some changes to the code and adding a test I got the following error when trying to debug the test:
Test result not found for: ./mylibs/integration_tests/myclient_integration_test.py::MyClientIntegrationTest::test_happy_path? An odd error message, to be sure.
After a little → Continue reading “VS Code “Test result not found for:” When Running Tests for a Python Project [SOLVED]”