perl linux command not working -

cat t.incopt.02.20110221 | awk -f, '{print $1}' | sort | uniq 

got unque records

but if inserted perl,

@fetch_req_details = `cat t.incopt.02.20110221 | awk -f\, '{print $1}' \| sort \| uniq`; 

if print above array vari, getting entire file content, guess linux command not working correctly when use inside perl,

i think need enclose command in tick , escape $

@fetch_req_details = `cat t.incopt.02.20110221 | awk -f, '{print \$1}' | sort | uniq;`