I was doing the batch FC analysis. I listed the subjects' covariables (9 variables) in a text file (Covlist.txt) as follows, 
C:\REST-analysis\Cov\Sub_001_detrend_filtered_cov.txt
C:\REST-analysis\Cov\Sub_002_detrend_filtered_cov.txt
C:\REST-analysis\Cov\Sub_003_detrend_filtered_cov.txt
C:\REST-analysis\Cov\Sub_004_detrend_filtered_cov.txt
......
C:\REST-analysis\Cov\Sub_017_detrend_filtered_cov.txt