We’ve all got to that point on a given system where we start to run out of storage space. Do we buy more storage, perhaps one of the best SSDs, or do we search and find the largest files quickly? In this how to we will look at a few simple approaches to help us maintain and manage our filesystems.
All the commands in this article will work on most Linux machines. We’ve used an Ubuntu LTS install but you could run this how-to on aRaspberry Pi. All of the how-to is performed via the Terminal. If you’re not already at the command line, you can open a terminal window on most Linux machines by pressingctrl, altandtor by searching for the terminal app in your applications menu.
Listing Files In Size Order Using the ls Command in Linux
Thelscommand is used to list the contents of a directory in Linux. By adding the-lSargument we can order the returned results according to the file size. We have copied a collection of files into atestdirectory to show this command but it can be run in any directory you choose.
To list the directory contents in descending file size order, use thelscommand along with the-ISargument.You will see the larger files at the top of the list descending to the smallest files at the bottom.
While this command is useful for seeing, it lacks the actual size of the files so how can we identify the largest files in Linux and display their size?
Identifying Files Larger Than a Specified Size in Linux
In another article, we explainedhow to find files in Linuxusing thefindcommand to search based on a filename or part of a filename. We can also use thefindcommand in combination with the-sizeargument specifying a size threshold where any file larger than specified will be returned.\
1.Usefindto search for any file larger than 100MB in the current directory.We are working inside ourtestdirectory and the “.” indicates to search the current directory. The-type fargument specifies returning files as results. Finally the+100Margument specifies that the command will only return files larger than 100MB in size. We only have one file in our test folderBaby_Yoda.objthat is larger than 100MB.
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2.Use the same command, but this time specify a path to search.We can run the same command as in the previous section but replace the “.” with a specified path. This means we can search thetestdirectory from thehomedirectory.
Searching the Whole Linux Filesystem For Large Files
It’s sometimes useful to search the wholeLinux filesystemfor large files. We may have some files hidden away in our home directory that need removing. To search the entire filesystem, we will need to use the command withsudo.We might also want to either limit the search to the current filesystem which can be achieved via the-xdevargument, for example when we suspect the files we seek are in our current main filesystem or we can choose not to add the-xdevargument which will then include results from other mounted filesystems, for example an attached USB drive.
1.Open a terminal.
2.Search the current filesystem for files larger than 100MB.As we are invoking root privileges usingsudowe will need to input our password. Note that we are using/to set the command to search the entire filesystem from theroot of the filesystem.
3.Search all filesystems for files larger than 100MB.For this example connect a USB drive with a collection of files on it including some that are over 100MB in size. You should be able to scroll through the returned results and see that the larger files on the pen drive have been included in the results.
Finding the 10 Largest Linux Files on Your Drive
What are the top ten files or directories on our machine? How large are they and where are they located? Using a little Linux command line magic we can target these files with only one line of commands.
2.Use theducommand to search all files and then use two pipes to format the returned data.
du -aBMwill search all files and directories, returning their sizes in megabytes.
/is the root directory, the starting point for the search.
2>/dev/nullwill send any errors to /dev/null ensuring that no errors are printed to the screen.
| sort -nris a pipe that sends the output ofducommand to be the input ofsortwhich is then listed in reverse order.
| head -n 10will list the top ten files/directories returned from the search.
3.Press Enter to run the command.It will take a little time to run as it needs to check every directory of the filesystem. Once complete it will return the top ten largest files / directories, their sizes and locations.
With this collection of commands, you have several ways to identify and locate large files in Linux. It’s extremely useful to be able to do this when you need to quickly select big files for deletion to free up your precious system resources. As always, take care when poking around your filesystem to ensure you aren’t deleting something critical!
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Jo Hinchliffe is a UK-based freelance writer for Tom’s Hardware US. His writing is focused on tutorials for the Linux command line.
