How to read df output, why Use% can reach 100% before Avail is zero for normal users, and how to check inodes with df -i.
df (disk free) is the standard command that shows the size, used space, available space and mount point of each mounted file system. 'df -h' prints sizes in human-readable units; 'df -i' shows inode usage instead of bytes, which explains 'No space left on device' errors when bytes are still free.
Filesystem is the device, Size the total, Used and Avail the space used and free for normal users, Use% the percentage, and Mounted on the directory where it appears.
On ext4, about 5% is reserved for root by default, so Used + Avail can be smaller than Size and normal users can run out before Use% shows 100%.
'-T' adds the file system type, '-x tmpfs' hides temporary memory file systems, and 'df -h /var' shows only the file system that holds /var.
df -hT -x tmpfsdf -iNote: RainServer offers monitoring and safe cleanup for Linux servers; it shows what will change and asks first.
Last updated: 2026-10-08
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