program demo_regmatch ! read regular expression from command line and look for it in lines read from stdin. use M_regex, only: regex_type, regcomp, regexec, regmatch, regfree implicit none integer :: command_argument_length character(len=:),allocatable :: command_argument character(len=1024) :: input_line type(regex_type) :: regex logical :: match integer,parameter :: max_subexpressions=10 integer :: matches(2,max_subexpressions) integer :: ios !find length of command argument call get_command_argument(number=1,length=command_argument_length) ! allocate a string long enough to hold the argument allocate(character(len=command_argument_length) :: command_argument) ! get the command argument call get_command_argument(1, command_argument) ! compile up regular expression call regcomp(regex,command_argument,'x') ! read lines and look for match to expression INFINITE: do read(*,'(a)',iostat=ios)input_line if(ios.ne.0)exit INFINITE ! look for a match in (remaining) string match=regexec(regex,input_line,matches) ! if no match found go for next line if(.not.match)cycle INFINITE ! show line with match write(*,'(a)') trim(input_line) enddo INFINITE ! free memory used for compiled regular expression call regfree(regex) end program demo_regmatch