Re: How to execute shell command and store result to variable?

EHLIM wrote: > > Hi Informix programmers, > > Can I run a Unix shell command like " ls .... | wc -l " and store the result > into a variable for my program varification purpose. So, if my program > checked that number of files in the directory were less than 3, prompt error > messages, otherwise continue. > > I tried this but it doesn't work:- > > LET run_txt="ls ..... | wc -l" > RUN run_txt RETURNING tot_file > IF tot_file < 3 THEN > ERROR "Incomplete files! Process aborted!" > SLEEP 3 > EXIT PROGRAM > END IF > > The variable tot_file shows value 1 means the shell command has been > sucessfully executed, but not the total number of files in the directory. Ehlim, I have no knowlege of any 4GL way to redirect the stdout of a program to a program variable. In my experience, I have seen such a capability in the various shells, AWK, and PERL.. so your request is a rather tall order. However, you can still get it if you are willing to break into C and do what the shell does: - open a pipe file - fork a child process - have the child proces redirect its stdout to the pipe - have the child process EXEC the program you want to run - Let the parent process capture the stdout of the child process - call pushquote and whatever else is needed to return a value to the calling 4GL routine - Smash your fist through the screen when it takes a week to debug this code. ;) well, there's probably a library function to do all the dirty work above; all you need to do is get the 4GL<->call/return conventions straight. For some situations, it might pay to have a special database table with many columns to serve as a communication area between programs. Of course, both programs would have to be database apps. This easy way out does not apply to your intention of running ordinary shell commands. Good luck. And if you find a UNIX library function to do that piping, spawning, and stdout-capture, please post a reply with the name of that function. -- -- Jake (Lost in thought and won't ask for directions) . . _..-'( )`-.._ ./'. '||\\\\. }\\_/{ .//||` .`\\. ./'.|'.'||||\\\\|.. )o o( ..|//||||`.`|.`\\. ./'..|'.|| |||||\\`````` \\,@,/ ''''''/||||| ||.`|..`\\. ./'.||'.|||| ||||||||||||. ||| .|||||||||||| ||||.`||.`\\. /'|||'.|||||| ||||||||||||{ | }|||||||||||| ||||||.`|||`\\ '.|||'.||||||| ||||||||||||{ | }|||||||||||| |||||||.`|||.` '.||| ||||||||| |/' ``\\||`` | ''||/'' `\\| ||||||||| |||.` |/' \\./' `\\./ \\!|\\ /|!/ \\./' `\\./ `\\| V V V }' `\\ /' `{ V V V \\ \\ \\ V / / / +-----------------------------------------------------------+ | Impeccable Logic: A thought process which successfully | | resists chicken bites | +-----------------------------------------------------------+