Unix: find largest files / folder to free up space

Unix boxes like to fill up with log files, and when they get really full, stuff starts to break. These commands will tell you where the big log files sit so you can delete them or gzip them.

first, in root run
df -k
/dev/md/dsk/d3 4129290 4020939 67059 99% /var

then go to /var and find what it taking up all the space:
du -sk * | sort -m | head
2855134 mail
..
193102 tmp

so mail is taking up space, now lets look for files bigger then 100MB:
find . -size +100000000c -ls
22615 483984 -rw-r--r-- 1 root other 495339455 Dec 14 15:09 ./mail/access_log
113593 209784 -rw-r--r-- 1 root other 214696853 Dec 14 15:08 ./mail/servletd.log
208492 354768 -rw-rw-rw- 1 admin mail 363091751 Dec 14 14:29 ./mail/admin

now you can see what is steal your megabytes.