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terminal

Running MySQL commands from the Terminal

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You can run MySQL commands from the terminal by using -e switch. Here are a few examples.

mysql -u username -p -e "create database mydb"
mysql -u username -p -e "use mydb"
mysql -u username -p database -e "select * from mytable"

If you have .mycnf configured, you can omit the username and password.

mysql -e "create database mydb"
mysql -e "use mydb"
mysql -e "select * from mytable"

To run multiple commands from a single line, separate the commands using a semicolon.

mysql -e "create database somedb; use mydb; select * from mytable;"

Linux Format USB Drive

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Here’s how to format a USB drive on Linux.

Plug in the USB drive to see mount point.

# scan for all drives
df -Th
Filesystem     Type     Size  Used Avail Use% Mounted on
/dev/sdc1      fuseblk   30G   66M   30G   1% /media/ulysses/451B99AF225B48EC

Unmount USB drive.

umount /dev/sdc1

Choose a file system type and run the appropriate format command.

# nfts format
mkfs.ntfs /dev/sdc1
# vfat format
mkfs.vfat /dev/sdc1
# ext4 format
mkfs.ext4 /dev/sdc1

Display Sequential Write Throughput

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Here’s a dd command to display sequential write throughput from the command line.

time dd if=/dev/zero of=/mounted_backup_volume/zero.raw bs=1M count=512 status=progress

Output is.

512+0 records in
512+0 records out
536870912 bytes (537 MB) copied, 0.667813 s, 804 MB/s
 
real    0m0.669s
user    0m0.000s
sys     0m0.359s

Audacity on Catalina

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If you’ve recently upgraded your Mac to Catalina or Mac OS 10.15.1, you may have noticed that Audacity is no longer working. To get it working, you’ll need to download version Audacity 2.3.3. However, installing and running it normally the way you’ve done it in the past will not be enough. Because of Catalina, Audacity is not able to gain permissions to the microphone inputs. The only way I was able to get it working is to launch Audacity from the Terminal.

Launch Audacity from the Terminal.

# cd to Application directory
cd /Applications/Audacity.app/Contents/MacOS
# Run it in the background
bash Audacity.sh &

Click Ok if prompted to use the microphone.

Can’t Empty The Trash Can

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If you have trouble emptying the trash this morning, here’s a helpful tip.

Your OS is essentially telling you the file is in use, but the application is close.

Nothing like running rm -rf on the trash folder.

# Go the trash directory and delete all!
cd ~/.Trash
rm -rf *

The file is gone!

Remove CleanMyMac

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Several months ago, I’ve installed an app called CleanMyMac. Big mistake. I didn’t like it much. I deleted it shortly after. The uninstall didn’t quite exactly remove everything. This morning, I updated my computer with the latest Mac updates. It required a reboot. Sure enough, the CleanMyMac notifications came back. Apparently, there’s some pieces of the app that are still running on my machine.

The only way I was able to delete anything related to the CleanMyMac app was to use a couple of tools. One is called Find Any File, a handy utility for finding obscure files in your OS. The other is the handy tool called the Terminal. Start with the Find Any File app and search for files that contain the words “CleanMyMac” and “macaw.” The Find Any File app will show you a list of files and their locations. You should be able to delete the files directly from the app. However, there are some files that are write-protected. They can be deleted using a sudo account on the Terminal.

Open up your Terminal and start deleting the files using “sudo rm” command. You’ll be ask to provide the admin password. Don’t forget to empty the Trash.

That should do the trick.