Linux disk visualization tool - ncdu
场景：磁盘空间占满后快速查找某个目录（子目录）占用空间大。
ncdu /var
（分析后按左右键查看即可）
ncdu 1.15.1 ~ Use the arrow keys to navigate, press ? for help
--- /var -------------------------------------
492.0 MiB [##########] /crash
165.4 MiB [### ] /lib
62.6 MiB [# ] /cache
46.9 MiB [ ] /opt
20.1 MiB [ ] /log
440.0 KiB [ ] /spool
20.0 KiB [ ] /tmp
12.0 KiB [ ] /kerberos
12.0 KiB [ ] /db
8.0 KiB [ ] /empty
e 4.0 KiB [ ] /yp
e 4.0 KiB [ ] /preserve
e 4.0 KiB [ ] /nis
e 4.0 KiB [ ] /local
e 4.0 KiB [ ] /gopher
e 4.0 KiB [ ] /games
e 4.0 KiB [ ] /ftp
e 4.0 KiB [ ] /adm
4.0 KiB [ ] .updated
@ 0.0 B [ ] lock
@ 0.0 B [ ] mail
@ 0.0 B [ ] run