How to find available space and free space if low [closed]

Question

I need to programmatically be able to see how much space is left on the SD card and if it is low delete some files. I'm not sure how to go about getting the value of the SD card space and then saving that as a variable to use in the if statement. I've read that df shows this info but how would I save that as a variable or get that info another way?

Ex:

available_space = #the available space on the sd card
If( available_space < 1gb):
      #delete old files 

Answer 1

To get the available disk space with python you could use psutil

import psutil

path = '/'
bytes_avail = psutil.disk_usage(path).free
gigabytes_avail = bytes_avail / 1024 / 1024 / 1024
print(gigabytes_avail)

If you look at the source code of the disk_usage function, you'll see they use os.statvfs().

To use statvfs yourself you could do something like this

import os

path = '/'
st = os.statvfs(path)

# free blocks available * fragment size
bytes_avail = (st.f_bavail * st.f_frsize)
gigabytes = bytes_avail / 1024 / 1024 / 1024
print(gigabytes)

Answer 2

Unless you provide a safe limitation (ie: "Only files in /mnt/volatile"), it's not a good idea to completely automate the removal of files. You can look into tmpwatch/tmpreaper on how Linux and different distributions create temporary files and directories, to hook into, or take advantage of the existing setup.

For example, if you can put unimportant files into /tmp/, they will be removed at reboot, and automatically by the system, over time, if space is needed.

GUI

Depending on your distribution and setup, you can try using baobab aka Disk Usage Analyzer.

baobab allows you to look into where data is located, either by disk, partition or directory. The visual nature makes it easier to investigate and find removable data than CLI solutions.

CLI

If you're interested in using the CLI, you can take a few approaches:

1. Use find to find files larger than a certain size.
2. Use du to look at files/directories.
   • -c for total
   • -d for depth
   • path/to/inspect/* Trailing * for directories
   • | sort -n Put largest files/directories at bottom
   • | tail -n 100 to limit the results

To look at a path and find the '20 'largest directories:

du /path/to/inspect/* | sort -nr | tail -n 20

You can drill down into directories you find:

$ du /path/to/inspect/* | sort -nr | tail -n 20
 ...
 /path/to/inspect/LargestDirectoryFound
$ du /path/to/inspect/LargestDirectoryFound/* | sort -n | tail -n 20

Once you determine how you like to find the files/directories, you will want to turn it into a bash function for easier use:

$ # Put this function in .bashrc after testing and tuning
$ function du-search(){
    # $@ is everything after the command
    du $@* | sort -n | tail -n 20
}
$ du-search /var/
 ...
$ du-search /var/INTERESTING_PATH/

By looking into du and the available options, you can show fewer duplicates and 'navigate' more quickly:

$ function du-search(){
    # $@ is everything after the command
    du -S -d0 $@* | sort -n | tail -n 20
}
$ du-search /var/
 ...
 /var/log
$ du-search /var/log/
 ...
 1820814528 /var/log/some_huge_logfile.log