I know this isn't a perl answer at all, but since you're looking for a oneliner how about using OpenSSL? From experience it's often available on many platforms. 
$ file datafile
datafile: PNG image data, 640 x 480, 8-bit colormap, non-interlaced
$ openssl base64 -e -in datafile >datafile.b64
$ file datafile.b64
datafile.b64: ASCII text
$ openssl base64 -d -in datafile.b64 >datafile2
$ md5sum datafile datafile2
c8f00e2b29d5b516d2c2afd8e41dcdfd  datafile
c8f00e2b29d5b516d2c2afd8e41dcdfd  datafile2

[download]
For all the options, see openssl base64 -h. I used to use openssl base64 to copy-paste small binary files between multiple terminal windows (using stdin/out rather than file for output/input), as doing it from the network was requiring multiple hops through intermediate servers. -- Thomas

In reply to Re: Base64 encode and decode by dermoth
in thread Base64 encode and decode by gio001

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