improve code by utilizing trace_readline_fields()
improve code by utilizing trace_readline_fields()

brendangregg/bcc,shodoco/bcc,brendangregg/bcc,mbudiu-bfn/bcc,tuxology/bcc,bpowers/bcc,bpowers/bcc,mshahbaz/bcc-deprecated,mkacik/bcc,romain-intel/bcc,mcaleavya/bcc,zaafar/bcc,zaafar/bcc,brendangregg/bcc,mcaleavya/bcc,mcaleavya/bcc,tuxology/bcc,bpowers/bcc,mbudiu-bfn/bcc,arslanabbasi/bcc,romain-intel/bcc,iovisor/bcc,tuxology/bcc,iovisor/bcc,mbudiu-bfn/bcc,zaafar/bcc,mcaleavya/bcc,mkacik/bcc,iovisor/bcc,romain-intel/bcc,tuxology/bcc,shodoco/bcc,mshahbaz/bcc-deprecated,arslanabbasi/bcc,iovisor/bcc,arslanabbasi/bcc,tuxology/bcc,romain-intel/bcc,mkacik/bcc,mbudiu-bfn/bcc,shodoco/bcc,mkacik/bcc,bpowers/bcc,brendangregg/bcc,zaafar/bcc,romain-intel/bcc,zaafar/bcc,mshahbaz/bcc-deprecated,bpowers/bcc,mshahbaz/bcc-deprecated,mshahbaz/bcc-deprecated,arslanabbasi/bcc,brendangregg/bcc,mbudiu-bfn/bcc,shodoco/bcc,mkacik/bcc,shodoco/bcc,mcaleavya/bcc,iovisor/bcc,arslanabbasi/bcc