конкатенация строк в bash

$ cat test1
zzzz

$ cat test2
aaaa

$ echo "`cat test1` `cat test2`" > test3
$ cat test3
zzzz aaaa

$> cat file1
aaa
aaa
aaa
aaa
aaa
aaa
aaa
aaa

$> cat file2
bbb
bbb
bbb
bbb
bbb
bbb
bbb
bbb

$> ghci
GHCi, version 7.4.2: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
(0.01 secs, 4323528 bytes)
Loading package filepath-1.3.0.0 ... linking ... done.
Loading package old-locale-1.0.0.4 ... linking ... done.
Loading package old-time-1.1.0.0 ... linking ... done.
Loading package bytestring-0.9.2.1 ... linking ... done.
Loading package unix-2.5.1.1 ... linking ... done.
Loading package directory-1.1.0.2 ... linking ... done.
Loading package process-1.1.0.1 ... linking ... done.
Loading package goa-3.1 ... linking ... done.
it :: ()
(0.06 secs, 7420664 bytes)
> putStrLn =<< unlines <$> map (\(a,b) → BSC.unpack $ BSC.unwords [a,b]) . uncurry zip <$> (uncurry (liftM2 (,)) $ join (***) ((BSC.lines <$>) . BSC.readFile) ("file1","file2"))
aaa bbb
aaa bbb
aaa bbb
aaa bbb
aaa bbb
aaa bbb
aaa bbb
aaa bbb

it :: ()
(0.01 secs, 5602744 bytes)

putStrLn =<< unlines . map (\(a,b) → unwords [a,b]) . uncurry zip <$> (uncurry (liftM2 (,)) $ join (***) ((lines <$>) . readFile) ("file1","file2"))

mapM_ putStrLn =<< let get = fmap lines . readFile in zipWith (\ a b -> a ++ "\t" ++ b) <$> get "aaa" <*> get "bbb"