PowerShell Cheatsheet

Operation cmd PowerShell
Get a simple directory listing
dir
get-childitem
alias: dir
Get a recursive directory listing
dir /s
get-childitem -recurse
alias: dir -r
Get a wide directory list
dir /w
dir | format-wide 
alias: dir | fw
List built-in commands
help
get-command
alias: help
Copy a file
copy foo.txt bar.txt
copy-item foo.txt bar.txt
alias: copy foo.txt bar.txt
Move a file
move foo.txt c:\
move-item foo.txt d:\
alias: move foo.txt d:\
Rename a file
ren foo.txt bar.txt
rename-item foo.txt bar.txt
alias: ren foo.txt bar.txt
Batch rename
ren *.one *.two
dir *.pdf | rename
  -newname {$_.name -rep ".one",".two"}
Set the current directory to d:\
d:
cd \
set-location d:\
alias: cd d:\
Clear the screen
cls
clear-host
alias: cls
List only directories
dir /ad
dir | where { $_.MshIsContainer }
Directory list, sorted by date
dir /od
dir | sort-object LastWriteTime
Directory list, sorted by date, descending order
dir /o-d
dir | sort-object LastWriteTime -desc
Show the current directory
cd
get-location
alias: pwd
See a command’s help
dir /?
get-help get-command 
or: get-help get-command -detailed
or: get-help get-command -full
or: dir -?
List environment variables
set
dir env:
Delete a file
del foo.txt
remove-item foo.txt
alias: del foo.txt
Find all *.txt files
dir /s *.txt
get-childitem -recurse -include *.txt
alias: dir -r -i *.txt
Find all *.txt files containing a particular string
findstr "foo" *.txt
dir *.txt | select-string "foo"
Show a list of services
net start
get-service
Start a service
net start MyService
start-service MyService
Stop a service
net stop MyService
stop-service MyService
Show network shares
net share
gwmi Win32_Share
Show a list of running processes
tasklist
get-process alias: ps
Kill all notepad.exe processes
taskkill /im notepad.exe /f
ps notepad | kill

 

Useful patterns for DateTime.ToString()

Custom DateTime.ToString() formats

d day of the month as a number from 1 through 31 – a single-digit day is formatted without a leading zero
dd day of the month as a number from 01 through 31 – a single-digit day is formatted with a leading zero
ddd abbreviated name of the day of the week (Mon, Tues, Wed etc)
dddd full name of the day of the week (Monday, Tuesday etc)
h 12-hour clock hour (e.g. 7)
hh 12-hour clock, with a leading 0 (e.g. 07)
H 24-hour clock hour (e.g. 19)
HH 24-hour clock hour, with a leading 0 (e.g. 19)
m minutes
mm minutes with a leading zero
M month number
MM month number with leading zero
MMM abbreviated Month Name (e.g. Dec)
MMMM full month name (e.g. December)
s seconds
ss seconds with leading zero
t abbreviated AM / PM (e.g. A or P)
tt AM / PM (e.g. AM or PM
y year, no leading zero (e.g. 2001 would be 1)
yy year, leadin zero (e.g. 2001 would be 01)
yyy year, (e.g. 2001 would be 2001)
yyyy year, (e.g. 2001 would be 2001)
K time zone information of a date and time value (e.g. +05:00)
z with DateTime values, represents the signed offset of the local operating system’s time zone from Coordinated Universal Time (UTC), measured in hours. (e.g. +6)
zz as z but with leadin zero (e.g. +06)
zzz with DateTime values, represents the signed offset of the local operating system’s time zone from UTC, measured in hours and minutes. (e.g. +06:00)
f most significant digit of the seconds fraction; that is, it represents the tenths of a second in a date and time value.
ff two most significant digits of the seconds fraction; that is, it represents the hundredths of a second in a date and time value
fff three most significant digits of the seconds fraction; that is, it represents the milliseconds in a date and time value
ffff four most significant digits of the seconds fraction; that is, it represents the ten thousandths of a second in a date and time value
fffff five most significant digits of the seconds fraction; that is, it represents the hundred thousandths of a second in a date and time value
ffffff six most significant digits of the seconds fraction; that is, it represents the millionths of a second in a date and time value
the seven most significant digits of the seconds fraction; that is, it represents the ten millionths of a second in a date and time value
F most significant digit of the seconds fraction; that is, it represents the tenths of a second in a date and time value. Nothing is displayed if the digit is zero.
: the time separator defined in the current DateTimeFormatInfo..::.TimeSeparator property. This separator is used to differentiate hours, minutes, and seconds.
/ date separator defined in the current DateTimeFormatInfo..::.DateSeparator property. This separator is used to differentiate years, months, and days.
quoted string (quotation mark). Displays the literal value of any string between two quotation marks (“). Your application should precede each quotation mark with an escape character (\).
quoted string (apostrophe). Displays the literal value of any string between two apostrophe (‘) characters.
%c the result associated with a c custom format specifier, when the custom date and time format string consists solely of that custom format specifier. That is, to use the d, f, F, h, m, s, t, y, z, H, or M custom format specifier by itself, the application should specify %d, %f, %F, %h, %m, %s, %t, %y, %z, %H, or %M. For more information about using a single format specifier, see Using Single Custom Format Specifiers.

The patterns for DateTime.ToString ( ‘d’ ) :

0 MM/dd/yyyy 08/22/2006

The patterns for DateTime.ToString ( ‘D’ ) :

0 dddd, dd MMMM yyyy Tuesday, 22 August 2006

The patterns for DateTime.ToString ( ‘f’ ) :

0 dddd, dd MMMM yyyy HH:mm Tuesday, 22 August 2006 06:30
1 dddd, dd MMMM yyyy hh:mm tt Tuesday, 22 August 2006 06:30 AM
2 dddd, dd MMMM yyyy H:mm Tuesday, 22 August 2006 6:30
3 dddd, dd MMMM yyyy h:mm tt Tuesday, 22 August 2006 6:30 AM

The patterns for DateTime.ToString ( ‘F’ ) :

0 dddd, dd MMMM yyyy HH:mm:ss Tuesday, 22 August 2006 06:30:07

The patterns for DateTime.ToString ( ‘g’ ) :

0 MM/dd/yyyy HH:mm 08/22/2006 06:30
1 MM/dd/yyyy hh:mm tt 08/22/2006 06:30 AM
2 MM/dd/yyyy H:mm 08/22/2006 6:30
3 MM/dd/yyyy h:mm tt 08/22/2006 6:30 AM

The patterns for DateTime.ToString ( ‘G’ ) :

0 MM/dd/yyyy HH:mm:ss 08/22/2006 06:30:07

The patterns for DateTime.ToString ( ‘m’ ) :

0 MMMM dd August 22

The patterns for DateTime.ToString ( ‘r’ ) :

0 ddd, dd MMM yyyy HH’:’mm’:’ss ‘GMT’ Tue, 22 Aug 2006 06:30:07 GMT

The patterns for DateTime.ToString ( ‘s’ ) :

0 yyyy’-‘MM’-‘dd’T’HH’:’mm’:’ss 2006-08-22T06:30:07

The patterns for DateTime.ToString ( ‘u’ ) :

0 yyyy’-‘MM’-‘dd HH’:’mm’:’ss’Z’ 2006-08-22 06:30:07Z

The patterns for DateTime.ToString ( ‘U’ ) :

0 dddd, dd MMMM yyyy HH:mm:ss Tuesday, 22 August 2006 06:30:07

The patterns for DateTime.ToString ( ‘y’ ) :

0 yyyy MMMM 2006 August

Best Practices for RESTful API

1. Use nouns but no verbs

For an easy understanding use this structure for every resource:

Resource GET
read
POST
create
PUT
update
DELETE
/cars Returns a list of cars Create a new car Bulk update of cars Delete all cars
/cars/711 Returns a specific car Method not allowed (405) Updates a specific car Deletes a specific car

2. GET method and query parameters should not alter the state

Use PUT, POST and DELETE methods  instead of the GET method to alter the state.

3. Use plural nouns

Keep it simple and use only plural nouns for all resources.

/users instead of /user

4. Use sub-resources for relations

If a resource is related to another resource use subresources.

GET /cars/711/drivers/ Returns a list of drivers for car 711

5. Use HTTP headers for serialization formats

Both, client and server, need to know which format is used for the communication. The format has to be specified in the HTTP-Header.

Content-Type defines the request format.
Accept defines a list of acceptable response formats.

6. Handle Errors with HTTP status codes

It is hard to work with an API that ignores error handling. Pure returning of a HTTP 500 with a stacktrace is not very helpful.

Use HTTP status codes

The HTTP standard provides over 70 status codes to describe the return values. We don’t need them all, but  there should be used at least a mount of 10.

200 – OK – Eyerything is working
201 – OK – New resource has been created
204 – OK – The resource was successfully deleted

304 – Not Modified – The client can use cached data

400 – Bad Request – The request was invalid or cannot be served. The exact error should be explained in the error payload. E.g. „The JSON is not valid“
401 – Unauthorized – The request requires an user authentication
403 – Forbidden – The server understood the request, but is refusing it or the access is not allowed.
404 – Not found – There is no resource behind the URI.
422 – Unprocessable Entity – Should be used if the server cannot process the enitity, e.g. if an image cannot be formatted or mandatory fields are missing in the payload.

500 – Internal Server Error – API developers should avoid this error. If an error occurs in the global catch blog, the stracktrace should be logged and not returned as response.

7. Provide filtering, sorting, field selection and paging for collections

Filtering:

Use a unique query parameter for all fields or a query language for filtering.

GET /cars?color=red Returns a list of red cars
GET /cars?seats<=2 Returns a list of cars with a maximum of 2 seats

Sorting:

Allow ascending and descending sorting over multiple fields.

GET /cars?sort=-manufactorer,+model

This returns a list of cars sorted by descending manufacturers and ascending models.

Field selection

Mobile clients display just a few attributes in a list. They don’t need all attributes of a resource. Give the API consumer the ability to choose returned fields. This will also reduce the network traffic and speed up the usage of the API.

GET /cars?fields=manufacturer,model,id,color

Paging

Use limit and offset. It is flexible for the user and common in leading databases. The default should be limit=20 and offset=0

GET /cars?offset=10&limit=5

To send the total entries back to the user use the custom HTTP header: X-Total-Count.

Three simple steps to enable Swagger on ASP.NET Core WebAPI

Step 1. Install NuGet package:

Install-Package Swashbuckle.AspNetCore

Step 2. Navigate to Startup.cs and add following code inside ConfigureServices() method


services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new Info { Title = "My API", Version = "v1" });
});

Step 3. Add following code inside Configure() method


app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
);

Voila!

Based on https://docs.microsoft.com/en-us/aspnet/core/tutorials/web-api-help-pages-using-swagger?tabs=visual-studio

Hello world!

let's scratch some heads...Welcome to my technical blog,

This is a very first post here (and I really hope not the last one).

Being in IT industry for a few years now, I realise more and more everyday that having good “knowledge base” is essential for any serious computer professional. Just look here if you do not believe my previous sentence.

Although I had collection of “hacks” and “tricks” it was allover the place. Some bits on my pc at work, some on laptop at home – that obviously is no good when you think “I definitely remember I did it, but how???”.

So the simplest answer to this problem was to create this “webspace”, which I hope also have some value for others as well.

If you by any luck found this place in a fantastic world of Internet, welcome! Feel more than encouraged to leave your fingerprint.

Matt