Wrap too long string output with new lines in bash

Question

Imagine your script outputs some real strange output like:

fdjsagnfafeowkagfdsngodagfoeagnfiosnthoaogjerapogrjeagnfdosngtnsrhig ofskhnIAGNRIEAGPREAOGJRIAEGRNIEOASGNFAIGRNESUIGRIOAEGRNIAENGRUEAOREANFDOIGNRUESIGORNAEIGNREIOAGRIUESGRJOEAGRNEOSIGRNEPAGRJAEIO

Crap I know. Probably it would look better this way:

fdjsagnfafeowkagfdsngodagfoeagnfiosnthoaogjera
pogrjeagnfdosngtnsrhig ofskhnIAGNRIEAGPREAOGJR
IAEGRNIEOASGNFAIGRNESUIGRIOAEGRNIAENGRUEAOREAN
FDOIGNRUESIGORNAEIGNREIOAGRIUESGRJOEAGRNEOSIGR
NEPAGRJAEIO

I am trying to do this with base64 encoded string data in bash. How could I do it?

Answer 1

For your sample input, fold will produce the output that you request. Suppose that we have this file:

$ cat longline
fdjsagnfafeowkagfdsngodagfoeagnfiosnthoaogjerapogrjeagnfdosngtnsrhig ofskhnIAGNRIEAGPREAOGJRIAEGRNIEOASGNFAIGRNESUIGRIOAEGRNIAENGRUEAOREANFDOIGNRUESIGORNAEIGNREIOAGRIUESGRJOEAGRNEOSIGRNEPAGRJAEIO

To make lines with width 46-characters:

$ fold -w 46 longline
fdjsagnfafeowkagfdsngodagfoeagnfiosnthoaogjera
pogrjeagnfdosngtnsrhig ofskhnIAGNRIEAGPREAOGJR
IAEGRNIEOASGNFAIGRNESUIGRIOAEGRNIAENGRUEAOREAN
FDOIGNRUESIGORNAEIGNREIOAGRIUESGRJOEAGRNEOSIGR
NEPAGRJAEIO

If you want to use it in a pipeline, fold also accepts stdin:

$ fold -w 46 <longline
fdjsagnfafeowkagfdsngodagfoeagnfiosnthoaogjera
pogrjeagnfdosngtnsrhig ofskhnIAGNRIEAGPREAOGJR
IAEGRNIEOASGNFAIGRNESUIGRIOAEGRNIAENGRUEAOREAN
FDOIGNRUESIGORNAEIGNREIOAGRIUESGRJOEAGRNEOSIGR
NEPAGRJAEIO

On Linux, fold is part of GNU coreutils and should be installed by default. It is also available under Mac OSX.