How to use Xcode for C and C++ development
Not only is Xcode an excellent IDE for iOS and macOS apps in both Swift and Objective-C; it does just as fine a job for regular C and C++ code. This includes all the features we know and love, such as code completion, version control, and all the rest of it. Let’s see how to use Xcode 8.3 for C and C++ development. Starting a new C Project Even the shortest programmes you’ll ever write with Xcode are a project. Everything’s a project in Xcode. Start a new one under File – New Project. Under the macOS tab, find the...
read moreHow to fix “can’t log into YouTube from Safari” on macOS
Something rather strange happened to me today: Safari 10 on macOS Sierra refused to let me login to YouTube. All it did was constantly refresh the page in an endless loop, or just display the front page of YouTube. I cleared the caches, reset the history, but no trick seemed to solve the problem. When I dug deeper into the Preferences, I found something under Privacy that finally fixed it. Let me share with you what worked on my system. head over to Safari – Preferences select the Privacy tab you’ll see a window like this one:...
read moreHow to rename a batch of files in Linux
Bulk renaming files can be done with the rename command. It shares many similarities with cp and mv, but its simplicity can be so staggering that its difficult to figure out how to use it. If we just type “rename” at the command prompt, all we get is the message rename call: rename from to files... While technically correct, what on earth does it mean? How do we use rename? Let’s do a little exercise. Imagine we had a batch of files, perhaps something like “Title 101.mp4” to “Title 110.mp4”....
read moreHow to exit VI with or without saving
Although many alternatives exist, I like using vi for all my command line editing needs. To save changes, I usually use SHIFT + Z + Z, exiting vi under most circumstances. But sometimes, this trick doesn’t work because of write permission problems. In such cases, vi doesn’t close with the above command. Instead, we must either stash our changes in another file, or quit the session without saving. Here’s how to do that. Quit vi without saving: :q! Save current file under a different name: :w newfile...
read moreHow to read command line parameters in BASH Scripts
Shell Scripts (BASH Scripts) can access command line parameters using the the variables $1, $2, $2 and so forth, up to $9. In fact, more parameters can be accessed by using curly brackets, like ${10}, ${187} and so forth. Here’s an example: #!/bin/bash if [[ $1 == "x" ]]; then echo "Statement is true" else echo "Statement is false" fi If we run the script with like this script.sh x it will tell us the statement is true. Otherwise, it’ll tell us the opposite. Note the whitespace around the evaluation:...
read moreHow to read command line parameters in PHP Shell Scripts
We can access parameters passed via the command line in our PHP shell scripts. Those are stored as an array in the variable $argv. Consider this: #!/usr/bin/php <?php echo var_dump($argv); echo "\n"; if ($argv[1] == 'x') { echo "The parameter is x."; } else { echo "The parameter was something else."; } The first part of the script prints out all parameters that have been given, while the second part checks if the parameter was “x” or not. Note that the first item in the array ($argv[0])...
read moreHow to extract files from a bz2 archive in Linux
If you’ve ever tried to decompress a file that ends in tar.bz2 using the tar command, you’ll have noticed that it doesn’t work. That’s because the tar command does not understand the binzip codec used in these archives. Instead, we can use the bzip2 command like so: bzip2 -d yourfile.tar.bz2 The -d switch stands for “decompress”. Notice that this will extract all files and delete the original .bz2 file by default. Very convenient indeed! If you’d like to keep it, just pass the -k switch (for...
read moreHow to start a Windows app with arguments from a shortcut
create a shortcut for your app somewhere right-click on the shortcut and head over to the Shortcut tab under Target, add your argument(s) after the closing quote hit OK, then double-click the shortcut...
read moreHow to remove duplicate packages with yum
I’m working on a handful of servers that all have the same problem: when running yum, an error message appears that tells me a package called ntpupdate needs to be upgraded, but somehow this doesn’t work and the package is being skipped. Then follows a huge list of duplicate packages that are installed on those systems (probably installed by the automatic package updater within Plesk). Let’s see how we can fix such issues. The Problem Here’s the output: yum update Loaded plugins: fastestmirror Loading mirror speeds...
read moreHow to mount and unmount drives in macOS and OS X from the command line
Unmounting external drives on a Mac is usually done quick and simple by either dragging drive icon to the trash, or by using the eject symbol in a Finder window. Mounting usually happens automatically when a new drive is inserted into a USB port or SD card slot. However, there is a way to do this via the command line, of which I am a big fan. Fire up a Terminal session and see how to do it. Listing available drives To see what’s currently attached to your Mac, let’s use the diskutil command, followed by the word list. You’ll...
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