How to create a new file containing contigs of a certain length from another contigs file

I have generated E coli contigs using Minia which contains contigs of all lengths. I want to create a new fasta file consisting of those contigs only which are greater than 400bp in length. Is there any way to do that.

The contigs generated by Minia is a fasta file and I want another filtered fasta file containing the contigs greater than 400bp only.