I am trying to combine 4 fastq.gz files in to one big file using following command.

    cat *.fastq.gz > File_Big.fastq.gz

However Every time I got following error 

    Error: object '.fastq.gz' not found

I made sure that I am working in correct directory.

Anyone have any idea where I am going wrong? 

Thanks 
You are using this command inside **R**.

Don't use R directly, using a linux shell. Like bash. https://www.tldp.org/LDP/Bash-Beginners-Guide/html/Bash-Beginners-Guide.html