Encode file content and echo it as one line

Question

I am trying to echo the content of key and certificate files encoded with base64 so that I can then copy the output into other places.

I found this thread: Redirecting the content of a file to the command echo? which shows how to echo the file content and also found ways to keep the newline characters for encoding. However when I add the | base64 this breaks the output into multiple lines, and trying to add a second echo just replaces the newlines with white spaces.

$ echo "$(cat test.key)" | base64
LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCk1JSUpRZ0lCQURBTkJna3Foa2lHOXcwQkFRRUZB
QVNDQ1N3d2dna29BZ0VBQW9JQ0FRRFF4Tkh0aHZvcEp1Z0EKOHBsSUNUUU1pOGMwMzRERlR6Z1E5
ME5tcE5zN2hRczNQZ0QwU2JuSFcyVGxqTS9oM1F1QVE0Q1dqaHRiV1ZUbgpSREcveGxWRFBESVVV
MzB1UHJnK0N6dlhOUkhzQkE9PQotLS0tLUVORCBQUklWQVRFIEtFWS0tLS0tCg==

$ echo $(echo "$(cat test.key)" | base64)
LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCk1JSUpRZ0lCQURBTkJna3Foa2lHOXcwQkFRRUZB QVNDQ1N3d2dna29BZ0VBQW9JQ0FRRFF4Tkh0aHZvcEp1Z0EKOHBsSUNUUU1pOGMwMzRERlR6Z1E5 ME5tcE5zN2hRczNQZ0QwU2JuSFcyVGxqTS9oM1F1QVE0Q1dqaHRiV1ZUbgpSREcveGxWRFBESVVV MzB1UHJnK0N6dlhOUkhzQkE9PQotLS0tLUVORCBQUklWQVRFIEtFWS0tLS0tCg==

The desired output would be:

LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCk1JSUpRZ0lCQURBTkJna3Foa2lHOXcwQkFRRUZBQVNDQ1N3d2dna29BZ0VBQW9JQ0FRRFF4Tkh0aHZvcEp1Z0EKOHBsSUNUUU1pOGMwMzRERlR6Z1E5ME5tcE5zN2hRczNQZ0QwU2JuSFcyVGxqTS9oM1F1QVE0Q1dqaHRiV1ZUbgpSREcveGxWRFBESVVVMzB1UHJnK0N6dlhOUkhzQkE9PQotLS0tLUVORCBQUklWQVRFIEtFWS0tLS0tCg==

How can I achieve this output?

Why does the base64 of a string contain “\n”? and What is wrong with echo $(stuff)? — Kamil Maciorowski, Feb 25 '20 at 09:16
Also "useless use of cat". Consider base64 -w 0 test.key or base64 -w 0 test.key; echo. — Kamil Maciorowski, Feb 25 '20 at 09:22

score 70 · Accepted Answer · answered Feb 25 '20 at 09:13

70

Use the -w option (line wrapping) of base64 like this:

... | base64 -w 0

A value of 0 will disable line wrapping.

answered Feb 25 '20 at 09:13

John Hawthorne

848

score 1 · Answer 2 · edited Oct 11 '21 at 13:52

1

Not all versions of base64 support the -w 0 flag (OSX), but the same effect of the -w 0 option is created by using:

cat test.key | base64

The output can be used for gitlab variables etc.

edited Oct 11 '21 at 13:52

AdminBee

22,803

answered Oct 10 '21 at 13:06

Wxll

111

score 0 · Answer 3 · answered Oct 07 '22 at 07:13

0

As mentioned before, not all versions of base64 support -w flag (https://www.fourmilab.ch/webtools/base64/).

That works for me:

base64 -e test.key | tr -d '\n\r'

answered Oct 07 '22 at 07:13

Patrick

101

You can tell echo to not add a new line to the end of the printed string:
echo -n "some_string" | base64
– M. Usatai Oct 30 '22 at 13:20
1

Yes, of course. But it's base64 that adds line breaks to the output. – Patrick Nov 03 '22 at 12:53

Encode file content and echo it as one line

3 Answers3