find command

Use: find . -type f -size +4096c
to find files bigger than 4096 bytes.

Use : find . -type f -size -4096c
to find files smaller than 4096 bytes. 

Use : find . -type f -size 4096c
to find files exactly equal to 4096 bytes. 

The -size switch explained: -size n[cwbkMG]. File uses n units of space. The following suffixes can be used: 

`b' for 512-byte blocks (this is the default if no suffix is used);

`c' for bytes

`w' for two-byte words 

`k' for Kilobytes (units of 1024 bytes)

`M' for Megabytes (units of 1048576 bytes)

`G' for Gigabytes (units of 1073741824 bytes) 

The size does not count indirect blocks, but it does count blocks in sparse files that are not actually allocated. Bear in mind that the `%k' and `%b' format specifiers of -printf handle sparse files differently. The `b' suffix always denotes 512-byte blocks and never 1 Kilobyte blocks, which is different to the behaviour of -ls.

Cited from http://superuser.com/questions/204564/how-can-i-find-files-that-are-bigger-smaller-than-x-bytes