Tech Reflect

Shell aliases are woefully underused. Painfully, I frequently see people do the following:

• Type a shell command with the same 4 arguments cd into the same folders
• ssh into the same machines or devices
• Run the same sequence of commands

Aliases are super easy. Just open your ~/.bashrc file (or equivalent) and start adding them. I’ll now give a bunch of examples I use.

“ls” command

I have many variations I use on the “ls” command. I don’t even remember what the arguments mean anymore because I’ve been using these shortcuts for so long.

# default arguments I like
alias l='ls -AG' 

# Long listing
alias ll='ls -aAlGh'

# Do a grep afterwards (My most often used)
alias lg='ls -AlGOh@ | grep -i '

# Newest files at bottom (My second most often used)
alias lt='ls -AltrGhu' 

# Largest files at bottom
alias lz='ls -AlGrhS' 

# Extended attributes

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If you’ve ever had a bizarre problem in Xcode and you’ve given up hope, this post is for you. Some frustrating things you might see:

• Breakpoints stop working
• A framework or library can’t be found that the compiler found moments ago
• Symbols in linked frameworks are no longer found
• This is not a comprehensive list.

I wrote this script a decade ago and in this frustrating moments, I run it, and go get a refreshing beverage while my computer reboots. It’s kind of unbelievable how often this has saved me. Maybe it will help you at least once in your life.

Note: Read the script first as it deletes your caches and DerivedData folder. It shouldn’t be a problem but you should be aware what it’s doing.

#!/bin/zsh

rm -rf ~/Library/Developer/Xcode/DerivedData 

#edit this to point to your DerivedData folder
rm -rf ~/Library/Caches/*Xcode*

sudo find /var/folders -iname xcode -exec mv \{\} 

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It’s fairly straightforward to leverage launchd to run a script either at specified intervals or at specific times of the day. I find that most people only want to do fairly simple things, so I’ve kept this simple.

The way launchd works is that you create a plist, then run a command to either load or unload the plist. Here is an example plist that will run the script called “rsync-backup-work” every 3 hours. The first 3 lines are just boilerplate for a plist.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
     "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
     <key>Label</key>
          <string>org.cricket.rsync-backup-work</string
     <key>ProgramArguments</key>
          <array>
               <string>/Users/admin/bin/rsync-backup-work</string
          </array>
     <key>StartInterval</key>
          <integer>10800</integer>
</dict>
</plist>

This has only three keys:

• Label → Unique identifier (this can just be the name of the plist without the plist suffix to make it simple)
• ProgramArguments → First item in the array is the path to an executable, the rest would be

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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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