How to decode base64 text in ldif file in Linux?

I need to decode base64 embedded in ldif (openldap) backups. I found here a way to join lines starting with a blank. Then, based on this question about "How to decode base64 text in xml file in Linux?" I want to decode the base64 strings, but I'm not being able to get it to work. My Script is: #Join lines starting with space sed -n 'H; ${ x; s/\n//; s/\n //g; p}' "$FILE" > "$FILE_JOINED" #Decode lines containing base64 (those with double colon) sed -r 's/(:: )([[:graph:]]+)/\1 '"grep -oP ':: [[:graph:]]+' "$FILE_JOINED" |cut -c 4- | base64 -d"'/g' "$FILE_JOINED" When I execute this, I get the following error: sed: -e expression #1, char 297: unknown option to `s' Here I add an example of the "$FILE_JOINED" contents: dn: olcDatabase={1}mdb,cn=config objectClass: olcDatabaseConfig objectClass: olcMdbConfig olcDatabase: {1}mdb olcDbDirectory: /var/lib/ldap olcSuffix: dc=proxy,dc=ldap olcAccess:: b25lIHZhbHVlCg== olcAccess: {1}to filter=(&(objectClass=securityPrincipal)(!(pwdAccountLockedTime=*))) attrs=userPassword,shadowLastChange by dn="cn=Man1,ou=local,dc=proxy,dc=ldap" write by anonymous auth by self write by * none olcAccess: {2} to * by * read olcAddContentAcl: FALSE olcLastMod: TRUE olcMaxDerefDepth: 15 olcReadOnly: FALSE olcRootDN: cn=Man1,ou=local,dc=proxy,dc=ldap olcRootPW:: dmFsdWUgdHdvCg== olcSyncUseSubentry: FALSE olcSyncrepl:: dmFsdWUgdGhyZWUK olcMirrorMode: TRUE dn: olcOverlay={0}unique,olcDatabase={1}mdb,cn=config objectClass: olcOverlayConfig objectClass: olcUniqueConfig (NOTE that the second command leaves the double colon (::) instead of leaving only one. I did it on purpose to be able to easily grep the output. I'll fix that later) The second command has a grep in it: How does it "select" the correct line to decode in all the file contents? Here is the result of the grep command alone: # grep -oP ':: [[:graph:]]+' x |cut -c 4- | base64 -d one value value two value three Could anybody please give me any pointers on how to decode the base64 values contained in a ldif file?