Tech Reflect

If you use multiple Macs, you may find yourself writing and editing scripts that could be useful on all of your machines. This is another potential use of iCloud Drive. Here’s what I do:

• I created a “bin” folder at the top level of my iCloud Drive
• I set up a symlink from my home directory to iCloud Drive on each of my machines using the same iCloud account:

ln -s /Users/admin/Library/Mobile\ Documents/com~apple~CloudDocs/bin ~/bin 

• I set up my shell config file to add ~/bin to the PATH variable.

export PATH=~/bin:/usr/bin:/bin:$PATH

• Start writing and editing scripts that are quickly available on all machines!

Related posts:

Many-to-many screensharing
Sharing shell settings between Macs
Multiple Macs, one location for screenshots

Multiple Macs, one location for screenshots

Sharing scripts between machines
Many-to-many screensharing
Sharing shell settings between Macs
Multiple Macs, one location for screenshots

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Spotlight can be powerful and fast, but lacks some precise control over the results. Typically you get far more results than you would ever need. The command-line interface unlocks more advanced functionality and you can also integrate it into your scripts.

The core command is “mdfind” and you could do “man mdfind” to see all the possibilties. However, here are a series of examples.

Simple

# Find every file that contains parakeet in the contents.

mdfind parakeet

# Restrict the search to a folder and ites subfolders (NOTE: Must be full path)

mdfind parakeet -onlyin /Users/admin/Pictures

# Display current matches and provide a live update when the number of matches changes. Great for testing you command but also to see live updates of things like a log file being created by your script.

mdfind parakeet -onlyin /Users/admin/Pictures -live

# Just display the live updating count. Less verbose and if 

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You can do some really interesting and time saving things using curly braces on the bash command line. Essentially, curly braces with a list of things separated by commas means run this command once for each item in the list.

This is best illustrated by a number of examples.

Create a complex folder hierarchy

mkdir -p folder/{1, 2, 3}/{a, b, c}

This creates this folder hierarchy:

folder/
     1/
          a/
          b/
     2/
          a/
          b/
     3/
          a/
          b/

Rename files in a hierarchy

This renames foo/bar/baz/1 to foo/bar/baz/2

mv foo/bar/baz/{1,2} 

Rename variation

This renames /foo/bar/baz/1 to foo/bar/tweedle/2

mv foo/bar/{baz/1, tweedle/2} 

Shortcut for adding extensions

This renames file to file1.backup

mv file1{.,backup}

Add extensions with wildcard matching

This will find files containing the word “banana” and slap an extension on them. This is an interesting case in that {,.bak} means add an extension.

find . -name "banana*" -exec mv \{\}{,.bak} \; 

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Depending on the situation, sometimes Finder can be the best way to interact with the file system and sometimes Terminal is better. There are a couple of little tricks for jumping.

Jump from Finder → Terminal

Tip #1

Terminal has two Services available called New Terminal Tab and New Terminal Tab at Folder.

With a folder selected in Finder, choose Finder → Services from the menu bar and choose one of the two options. Note this is quickly accessed in the contextual menu. This causes a Terminal window or tab to open, rooted at the folder you chose.

You’ll note that one of the commands has a keyboard shortcut. You can set this up in System Preferences → Keyboard → Shortcuts → Services

Tip #2

If you’re drag-n-drop oriented, you can drag any folder into an open Terminal window and the path will get pasted in. If your goal is to …

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The shells you hear about the most, like bash, tcsh, and zsh aren’t the only shells out there. For about 5 years, I’ve used a shell called fish. While the community of people using it is quite small, it’s a passionate group and the shell has some features you’ll wonder how you lived without.

You can download it here.

Fish shell

The cheeky headline on the pages pokes fun at other shells. The documentation is excellent and worth perusing.

I like to describe it as the Apple of shells. Even though it’s possible to get many fish features in other shells, it typically involves many trips to Stack Overflow or borrowing people’s shell files. The fish shell tends to make these the default or make it easier to set them up.

Advantages

• Many of the common things people want are enabled by default, like case-insensitive completion on the command-line
• Tab-completion

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This one is a bit crazy, so be careful. Read on if you fall into most of these categories:

• You have multiple Macs
• You frequently make changes to .bash_profile (or equivalent)
• You’d love to have your shell history shared between machines for tab completion
• You have an iCloud account shared on all your Macs
• You like to live a little dangerously

Iʼve been running this way over 10 years and have never run into problems, other than syncing sometimes being sluggish. However, most of the time it’s so fast that it’s amazing.

If your shell files get messed up during the setup and you can’t get to a command prompt, you can do the following:

• Launch Terminal
• Go to Preferences -> General
• Change the “Shells open with”setting to specify a complete path.
• Use a different shell path like /bin/tcsh or /bin/zsh.
• Then, fix the problem if you know what

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When people want to kill processes from the command line, I typically see them:

• Run the ps command, with or without flags, and with or without grep
• Sift through the results if there is more that one
• Grab the pid and run “kill <pid>“
• Repeat the steps to kill other similar processes

There are a few other commands that are more sophisticated than kill and will save you time.

killall

# kill all processes with that name (so you don't need the PID)
killall <exact process name>

# kill all processes that match a regex
killall -m <expression>

# Test the command ahead of time rather than running it
killall -s 

pkill (and pgrep)

# show all processes that match the expression
pgrep <expression>

# kill processes that match
pkill <expression>

# match full argument lists, so you could kill processes within a specific folder hierarchy, for example

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The find command is one of those utilities that, if you know it well, is one of the most powerful tools in your toolchest. However, with a man page nearly 600 lines long and somewhat bewildering syntax, it’s very intimidating. Sometimes the simplest options you are looking for can be oddly named or unexpected.

I created a series of examples of how to do some very basic stuff with the find command, which is what most people really want to do. Each example builds on the previous one. Once you get comfortable, then you can look at the man page and add new options one at a time to get the hang of it.

# Find a file that contains the string "banana" in the current directory and all subdirectories
find . -name "*banana*"

# Search case insensitively
find . -iname "*banana*"

# Search only in the current directory
find 

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This question comes up often on Swift mailing lists. Once you learn Swift, you’ll get addicted and want to use it everywhere. It’s not quite as straightforward writing a script in Swift as it is in python or bash. However, there are lots of benefits.

• It’s a great entry point into learning Swift for those that typically write scripts rather than applications
• You want to execute a bunch of shell commands, but you can use Swift’s rich data structures, straightforward programming language, and the huge Cocoa API.

Here’s what you can do:

• Launch Xcode
• File > New > ProjectChoose macOS
• Click on Command Line Tool
• Name it and save the project

• Click on main.swift in the sidebar
• Replace the Hello, World line with this code.

import Foundation

struct Shell {
     func stripWhitespace(_ inString: String) -> String {
         return inString.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
     }

     func executeCommand(_ command:String, echo: Bool = true) -> 

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