Linux: cómo agregar contenido de varios archivos en uno

Ejemplo tenemos muchos archivos html:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 dieciséis 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 sesenta y cinco 66 67 68

[root@tutorialspots ok]# ls backup_okru0.html             backup_okru_type_432001.html backup_okru1001.html          backup_okru_type_432501.html backup_okru1501.html          backup_okru_type_433001.html backup_okru2001.html          backup_okru_type_433501.html backup_okru2501.html          backup_okru_type_434001.html backup_okru3001.html          backup_okru_type_434501.html backup_okru3501.html          backup_okru_type_435001.html backup_okru4001.html          backup_okru_type_43501.html backup_okru4501.html          backup_okru_type_435501.html backup_okru5001.html          backup_okru_type_436001.html backup_okru501.html           backup_okru_type_436501.html backup_okru5501.html          backup_okru_type_437001.html backup_okru6001.html          backup_okru_type_437501.html backup_okru6501.html          backup_okru_type_438001.html backup_okru7001.html          backup_okru_type_438501.html backup_okru7501.html          backup_okru_type_439001.html backup_okru8001.html          backup_okru_type_439501.html backup_okru8501.html          backup_okru_type_440001.html backup_okru_type_40.html      backup_okru_type_44001.html backup_okru_type_410001.html  backup_okru_type_440501.html backup_okru_type_41001.html   backup_okru_type_441001.html backup_okru_type_410501.html  backup_okru_type_441501.html backup_okru_type_411001.html  backup_okru_type_442001.html backup_okru_type_411501.html  backup_okru_type_442501.html backup_okru_type_412001.html  backup_okru_type_443001.html backup_okru_type_412501.html  backup_okru_type_443501.html backup_okru_type_413001.html  backup_okru_type_444001.html backup_okru_type_413501.html  backup_okru_type_444501.html backup_okru_type_414001.html  backup_okru_type_445001.html backup_okru_type_414501.html  backup_okru_type_44501.html backup_okru_type_415001.html  backup_okru_type_445501.html backup_okru_type_41501.html   backup_okru_type_446001.html backup_okru_type_415501.html  backup_okru_type_446501.html backup_okru_type_416001.html  backup_okru_type_447001.html backup_okru_type_416501.html  backup_okru_type_447501.html backup_okru_type_417001.html  backup_okru_type_448001.html backup_okru_type_417501.html  backup_okru_type_448501.html backup_okru_type_418001.html  backup_okru_type_449001.html backup_okru_type_418501.html  backup_okru_type_449501.html backup_okru_type_419001.html  backup_okru_type_450001.html backup_okru_type_419501.html  backup_okru_type_45001.html backup_okru_type_420001.html  backup_okru_type_4501.html backup_okru_type_42001.html   backup_okru_type_450501.html backup_okru_type_420501.html  backup_okru_type_451001.html backup_okru_type_421001.html  backup_okru_type_451501.html backup_okru_type_421501.html  backup_okru_type_452001.html backup_okru_type_422001.html  backup_okru_type_452501.html backup_okru_type_422501.html  backup_okru_type_453001.html backup_okru_type_423001.html  backup_okru_type_453501.html backup_okru_type_423501.html  backup_okru_type_454001.html backup_okru_type_424001.html  backup_okru_type_454501.html backup_okru_type_424501.html  backup_okru_type_455001.html backup_okru_type_425001.html  backup_okru_type_45501.html backup_okru_type_42501.html   backup_okru_type_455501.html backup_okru_type_425501.html  backup_okru_type_456001.html backup_okru_type_426001.html  backup_okru_type_456501.html backup_okru_type_426501.html  backup_okru_type_457001.html backup_okru_type_427001.html  backup_okru_type_457501.html backup_okru_type_427501.html  backup_okru_type_46001.html backup_okru_type_428001.html  backup_okru_type_46501.html backup_okru_type_428501.html  backup_okru_type_47001.html backup_okru_type_429001.html  backup_okru_type_47501.html backup_okru_type_429501.html  backup_okru_type_48001.html backup_okru_type_430001.html  backup_okru_type_48501.html backup_okru_type_43001.html   backup_okru_type_49001.html backup_okru_type_430501.html  backup_okru_type_49501.html backup_okru_type_431001.html  backup_okru_type_431501.html

¿Cómo unirlos en un solo archivo?

1	cat *.html > ok.txt