Two quick and dirty ways to capture the output of a system call from Nu.

gistfile1.txt

(set popen (NuBridgedFunction functionWithName:"popen" signature:"l**"))
(set pclose (NuBridgedFunction functionWithName:"pclose" signature:"il"))
(set fgetc (NuBridgedFunction functionWithName:"fgetc" signature:"il"))

(set mktemp (NuBridgedFunction functionWithName:"mktemp" signature:"**"))
(set unlink (NuBridgedFunction functionWithName:"unlink" signature:"i*"))

(function sys (command)
    (set tempfile (mktemp "temp.XXXXXX"))
    (set c (+ "(" command " 2>&1) > " tempfile))
    (system c)
    (set o (NSString stringWithContentsOfFile:tempfile))
    (unlink tempfile)
    o)  

(function sysp (command *options)
    (set task ((NSTask alloc) init))
    (set targs (NSArray arrayWithList:*options))
    (set p (NSPipe pipe))
        
    (task setLaunchPath:command)
    (task setArguments:targs)
    (task setStandardOutput:p)
    (set fp (p fileHandleForReading))

    (task launch)

    (set d (fp readDataToEndOfFile))

    (set o ((NSString alloc) initWithData:d encoding:NSUTF8StringEncoding))
    o)  

(set o (sys "ls"))
(puts o)

(set o (sysp "/bin/ls" "-l" "-a"))
(puts o)