Generating a sha256 from the Linux command line [closed]

Question

I know the string "foobar" generates the SHA 256 hash c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2 using http://hash.online-convert.com/sha256-generator

However the command line shell:

hendry@x201 ~$ echo foobar | sha256sum 
aec070645fe53ee3b3763059376134f058cc337247c978add178b6ccdfb0019f  -

Generates a different hash. What am I missing?

Answer 1

echo will normally output a newline, which is suppressed with -n. Try this:

echo -n foobar | sha256sum

Answer 2

If you have installed openssl, you can use:

echo -n "foobar" | openssl dgst -sha256

For other algorithms you can replace -sha256 with -md4, -md5, -ripemd160, -sha, -sha1, -sha224, -sha384, -sha512 or -whirlpool.

Answer 3

If the command sha256sum is not available (on mavericks for example), you can use :

echo -n "foobar" | shasum -a 256

Answer 4

echo -n works and is unlikely to ever disappear due to massive historical usage, however per recent versions of the POSIX standard, new conforming applications are "encouraged to use printf".

Answer 5

echo produces a trailing newline character which is hashed too. try:

/bin/echo -n foobar | sha256sum 

Answer 6

I believe that echo outputs a trailing newline. Try using -n as a parameter to echo to skip the newline.