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Swift: if let url = URL(string: "mailto://azimov@demo.com") { if UIApplication.shared.canOpenURL(url) { UIApplication.shared.openURL(url) } else { print("Cannot open URL") } } Objective-C: NSURL *url = [NSURL URLWithString:@"mailto://az...

This variable will give you a total number of fields in the current input record. awk -F',' '{print NF}' file.csv Example: $ cat file.csv col1,col2,col3,col4 col1,col2,col3 col1,col2 col1 col1,col2,col3,col4,col5 $ awk -F',' '{print NF}' file.csv 4 3 2 1 5

Use "-x" to enable debug output of executed lines. It can be run on an entire session or script, or enabled programmatically within a script. Run a script with debug output enabled: $ bash -x myscript.sh Or $ bash --debug myscript.sh Turn on debugging within a bash script. It may ...

Whitespace matters when assigning variables. foo = 'bar' # incorrect foo= 'bar' # incorrect foo='bar' # correct The first two will result in syntax errors (or worse, executing an incorrect command). The last example will correctly set the variable $foo to the text "bar".

Popular within many open source projects but not only. Master branch of a specific location (Github, Gitlab, Bitbucket, local server) contains the latest shippable version. For each new feature/bug fix/architectural change each developer creates a branch. Changes happen on that branch and can be d...

To execute a script file with the bash interpreter, the first line of a script file must indicate the absolute path to the bash executable to use: #!/bin/bash The bash path in the shebang is resolved and used only if a script is directly launch like this: ./script.sh The script must have exe...

To execute a script file with the bash executable found in the PATH environment variable by using the executable env, the first line of a script file must indicate the absolute path to the env executable with the argument bash: #!/usr/bin/env bash The env path in the shebang is resolved and used...

Will provide the total number of records processed in the current awk instance. cat > file1 suicidesquad harley quinn joker deadshot cat > file2 avengers ironman captainamerica hulk awk '{print NR}' file1 file2 1 2 3 4 5 6 7 8 A total on 8 records were processed in th...

Provides the total number of records processed by the awk instance relative to the files awk is processing cat > file1 suicidesquad harley quinn joker deadshot cat > file2 avengers ironman captainamerica hulk awk '{print FNR}' file1 file2 1 2 3 4 1 2 3 4 Each file had...

Provides the number of columns or fields in each record (record corresponds to each line). Each line is demarcated by RS which defaults to newline. cat > file1 Harley Quinn Loves Joker Batman Loves Wonder Woman Superman is not dead Why is everything I type four fielded!? awk '{print NF}' ...

Press controlr and type a pattern. For example, if you recently executed man 5 crontab, you can find it quickly by starting to type "crontab". The prompt will change like this: (reverse-i-search)`cr': man 5 crontab The `cr' there is the string I typed so far. This is an incremental s...

If you need to add custom headers to your volley requests, you can't do this after initialisation, as the headers are saved in a private variable. Instead, you need to override the getHeaders() method of Request.class as such: new JsonObjectRequest(REQUEST_METHOD, REQUEST_URL, REQUEST_BODY, RESP_L...

Configure your app's URLconf to automatically use a URL namespace by setting the app_name attribute: # In <myapp>/urls.py from django.conf.urls import url from .views import overview app_name = 'myapp' urlpatterns = [ url(r'^$', overview, name='overview'), ] This will set t...

NOTE: This is only available in Scala 2.12+ (and in recent 2.11.x versions with the -Xexperimental -Xfuture compiler flags) A SAM type can be implemented using a lambda: 2.11.8 trait Runnable { def run(): Unit } val t: Runnable = () => println("foo") The type can optional...

Setup First, install the necessary packages with: npm install express cors mongoose Code Then, add dependencies to server.js, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB: var express = require('express'); var cors = require('...

The dot operator repeats the last action performed, for instance: file test.tx helo, World! helo, David! (cursor at [1][1]) Now perform a cwHello<Esc> (Change Word helo to Hello) Now the buffer looks like that: Hello, World! helo, David! (cursor at [1][5]) After typing j_ the cur...

You might have heard that everything in Python is an object, even literals. This means, for example, 7 is an object as well, which means it has attributes. For example, one of these attributes is the bit_length. It returns the amount of bits needed to represent the value it is called upon. x = 7 ...

<svg width="900px" height="400px" viewBox="900 400"> <defs> <filter id="GaussianHardEdge" x="0%" y="0%" width="100%" height="100%"> <feGaussianBlur stdDeviation="5"/&gt...

<svg width="900px" height="400px" viewBox="900 400"> <defs> <filter id="GaussianHardEdge" > <feConvolveMatrix order="3" kernelMatrix=" 1 1 1 1 1 1 ...

<svg width="900px" height="400px" viewBox="0 0 900 400"> <defs> <filter id="BokehBlur" color-interpolation-filters="sRGB"> <feGaussianBlur stdDeviation="2" result="blurSource"/> <feCol...