Finding file and directory in ubuntu

To find a file in your system by name use below command -

find -name "query"

For case insensitive search -

find -iname "query"

Search by extension -

find / -type f -name "*.txt"

Search by size -

find / -size 50c

  c - byte
  k - kilo byte
  M - mega byte
  G - giga byte

less than 50 byte

find / -size -50c

more than 50 Mb

find / -size +50M

Search by time -
can be searched on three time basis
Access Time -atime
Modification time -mtime , when file content is changed.
Change time -ctime , when metadata , inode data is chaged.

Modified 1 day ago -

find / -mtime 1

Accessed less than 1 day ago -

find / -atime -1

Finding by owner -

find / -user username

Finding by permission -

find / -perm 644

Finding files by using command locat

locate filename

locate -b basefilename

Find a directory by name -

find / -name directoryname -type d