Generating a Sha-256 Hash from the Linux Command Line
I Know the String "Foobar" Generates the Sha-256 Hash C3Ab8Ff13720E8Ad9047Dd39466B3C8974E592C2Fa383D4A3960714Caef0C4F2 Using However the Command Line Shell...
I know the string "foobar" generates the SHA-256 hash c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2 using
However the command line shell:
hendry@x201 ~$ echo foobar | sha256sum
aec070645fe53ee3b3763059376134f058cc337247c978add178b6ccdfb0019f -
Generates a different hash. What am I missing?
8 Answers
echo will normally output a newline, which is suppressed with -n. Try this:
echo -n foobar | sha256sum
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.
If the command sha256sum is not available (on Mac OS X v10.9 (Mavericks) for example), you can use:
echo -n "foobar" | shasum -a 256
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".
echo produces a trailing newline character which is hashed too. Try:
/bin/echo -n foobar | sha256sum
For the sha256 hash in base64, use:
echo -n foo | openssl dgst -binary -sha256 | openssl base64
Example
echo -n foo | openssl dgst -binary -sha256 | openssl base64
C+7Hteo/D9vJXQ3UfzxbwnXaijM=
I believe that echo outputs a trailing newline. Try using -n as a parameter to echo to skip the newline.
Use printf instead of echo to avoid adding an extra newline.
printf foobar | sha256sum
James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.
