Cleaning space on Linux board (SD memory)

Check available space - none left

# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       3.5G  3.3G     0 100% /

List files in a suspicious directory by SIZE:

# ls -alS

Remove biggest offenders

# rm -rf /var/cores/*

# rm -rf /var/log/*

Check space available - 89% utilization

# df -hFilesystem     

Size  Used Avail Use% Mounted

on/dev/root       3.5G  3.0G  370M  89% /