How to show the largest files under a directory on Mac OS X (Unix) alvin December 23, 2017 - 1:00pm

Here’s an example that shows how to find the largest files under a directory on MacOS and Linux/Unix systems.

A du/sort command to show the largest files under a directory on Mac OS X

The Unix/Linux command that worked for me on my MacOS system is this:

$ du -a * | sort -r -n | head -10

du is the disk usage command, and the -a flag says, “Display an entry for each file in a file hierarchy.” Then I use the sort command to sort the du output numerically and in reverse. After that, head -10 shows only the first ten lines of output. In the Music folder on my Mac the command and output look like this:

Linux: Recursive file searching with grep -r (like grep + find)

Linux grep FAQ: How can I perform a recursive search with the grep command in Linux?

Solution: find + grep

For years I always used variations of the following Linux find and grep commands to recursively search subdirectories for files that match a grep pattern:

find . -type f -exec grep -l 'alvin' {} \;

This command can be read as, “Search all files in all subdirectories of the current directory for the string ‘alvin’, and print the filenames that contain this pattern.” It’s an extremely powerful approach for recursively searching files in all subdirectories that match the pattern I specify.

A Linux shell script (and commands) to find large files

I made a mistake in configuring logrotate on a new Linux system, and almost ran into a problem because of that. Fortunately I saw the problem before it became a BIG problem, but as a result, I decided to add a script to my Linux system to check for large files, typically log files that have grown out of control for one reason or another.

Here then is a simple Linux shell script I named, which searches the filesystem for files that are larger than 1GB in size:

A Linux shell script to rename files with a counter and copy them

As a brief note today, I was recently looking for all Messages/iMessage files that are stored on my Mac, and I used this shell script to copy all of those files — many of which have the same name — into a directory named tmpdir, giving them all new names during the copy process:

for i in `cat myfiles`
    fname=`basename $i`
    cp $i tmpdir/${count}-${fname}
    count=`expr $count + 1`
SBT errors summary plugin alvin July 4, 2017 - 8:01am

The sbt-errors-summary plugin looks cool. Here’s a summary from its author:

“A simple plugin that makes the error reporter a bit more concise. I find it useful when doing refactoring: I get a lot of compilation errors, and I waste a lot of time switching between files and looking for line numbers in the error message, when I can immediately see what's wrong when looking at the faulty line.”

How to search multiple jar files for a string or pattern (shell script)

Here’s a Unix shell script that I use to search Java Jar files for any type of string pattern. You can use it to search for the name of a class, the name of a package, or any other string/pattern that will show up if you manually ran jar tvf on each jar file. The advantage of this script — if you’re a Unix, Linux, or Cygwin user — is that it will search through all jar files in the current directory:

Unix: How to find files with multiple filename extensions

As I mentioned in my How to find multiple filenames with Linux find tutorial, you can use find command syntax like this to find files with multiple filename extensions:

find iTunes \( -name "*.mp3" -o -name "*.m4a" \)

As that command shows, I ran this find command to find all of my music files under my iTunes directory, including .mp3 and .m4a filename extensions.

While I’m in the neighborhood, this is the full find command I use to backup all of my iTunes files that have changed or been added in the last 180 days:

find iTunes \( -name "*.mp3" -o -name "*.m4a" \) -type f -mtime -180 -print0 | xargs -0 tar rvf NewMusic.tar

There’s probably an easier way to do this, but that backup command works for me.

A Unix find and move command (find in subdirectories)

This is a dangerous Unix command, but if you want to move a bunch of files from their subdirectories into your current directory, this find and mv command works:

find . -type f -exec mv {} . \;

That command finds all files beneath the current directory, and moves them into the current directory. I just moved a bunch of files from their (iTunes) subdirectories into my current working directory, and that find and move command did the trick. (But again, it’s a dangerous command, be careful out there.)

Git - How to automatically `git rm` all files that have been deleted on disk alvin January 13, 2016 - 8:00pm

This SO tip on how to automatically remove/delete all files from a Git repository that you have already deleted on disk is a real timesaver. Of course it’s a wee bit dangerous (and probably won’t work on Windows), but that’s part of its charm.