GNU's base64 -d requires proper padding (input length must be a multiple of 4). Other bash64 decoders may be smarter and not require padding (e.g. Mac/BSD bash64 -D does not require padding).

Here's a bash command that can automatically pad the base64 string properly. Then you won't get the "invalid input" error.

str="eyJmb28iOiJiYXIiLCJiYXoiOiJiYXQifQ"

echo "$str"==== | fold -w 4 | sed '$ d' | tr -d '\n' | base64 --decode

Explanation:

• echo "$str"==== appends 4 equal signs
• fold -w 4 split every 4 characters into separate lines
• sed '$ d' deletes the last line (the extraneous padding)
• tr -d '\n' joins all lines

GNU's base64 -d requires proper padding (input length must be a multiple of 4). Other base64 decoders may be smarter and not require padding (e.g. Mac/BSD base64 -D does not require padding).

Here's a bash command that can automatically pad the base64 string properly. Then you won't get the "invalid input" error.

str="eyJmb28iOiJiYXIiLCJiYXoiOiJiYXQifQ"

echo "$str"==== | fold -w 4 | sed '$ d' | tr -d '\n' | base64 --decode

Explanation:

• echo "$str"==== appends 4 equal signs
• fold -w 4 split every 4 characters into separate lines
• sed '$ d' deletes the last line (the extraneous padding)
• tr -d '\n' joins all lines