Failed to open snp_1_22.txt

[TareqAldirawi]

Hi,
I am running the codes and I got an error in the following code:

Step 3

Generate bfile with autosomal SNPs only and delete SNPs with a low minor allele frequency (MAF).

Select autosomal SNPs only (i.e., from chromosomes 1 to 22)

system("awk '{ if ($1 >= 1 && $1 <= 22) print $2 }' HapMap_3_r3_6.bim > snp_1_22.txt")
system("plink --bfile HapMap_3_r3_6 --extract snp_1_22.txt --make-bed --out HapMap_3_r3_7")

The error is:
Error: Failed to open snp_1_22.txt.