How to measure the total size of a fastq file in base pairs?
I've been using this:
cat file.fastq | paste - - - - | cut -f 2 | tr -d '\n' | wc -c 
Explanation :

paste - - - - : print four consecutive lines in one row (tab delimited), to merge the info for each read

cut -f2 : print only the second column, to access the sequence after the paste

wc -c : count the characters

tr -d '\n': to remove from count the eventual newline characters


(a tip for your googling: try search for &quot;counting number of bases in fastq file&quot;)