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linuxshellsha256
hendry
hendry

Reputation: 10843

Generating a SHA-256 hash from the Linux command line

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?

Upvotes: 385

Views: 566922

Answers (8)

Farahmand
Farahmand

Reputation: 2991

If you have installed openssl, you can use:

echo -n "foobar" | openssl dgst -sha256

For other algorithms you can replace -sha256 with:

  • -blake2b512
  • -blake2s256
  • -md4
  • -md5
  • -md5-sha1
  • -ripemd
  • -ripemd160
  • -rmd160
  • -sha1
  • -sha224
  • -sha256
  • -sha3-224
  • -sha3-256
  • -sha3-384
  • -sha3-512
  • -sha384
  • -sha512
  • -sha512-224
  • -sha512-256
  • -shake128
  • -shake256
  • -sm3
  • -ssl3-md5
  • -ssl3-sha1
  • -whirlpool

The list of all algorithms can be found from here:

openssl dgst -list

Upvotes: 141

Unmitigated
Unmitigated

Reputation: 89442

Use printf instead of echo to avoid adding an extra newline.

printf foobar | sha256sum

For an arbitrary string, the %s format specifier should be used.

printf '%s' 'somestring' | sha256sum

Upvotes: 17

stevec
stevec

Reputation: 52768

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=

Upvotes: 19

Sucrenoir
Sucrenoir

Reputation: 3034

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

Upvotes: 57

Nordic Mainframe
Nordic Mainframe

Reputation: 28767

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

/bin/echo -n foobar | sha256sum

Upvotes: 14

mvds
mvds

Reputation: 47114

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

echo -n foobar | sha256sum

Upvotes: 603

Nicholas Knight
Nicholas Knight

Reputation: 16045

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".

Upvotes: 39

Thomas Owens
Thomas Owens

Reputation: 116187

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

Upvotes: 9

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