% tpm2_pcrevent(1) tpm2-tools | General Commands Manual

# NAME

**tpm2_pcrevent**(1) - Hashes a file and optionally extends a pcr.

# SYNOPSIS

**tpm2_pcrevent** [*OPTIONS*] _FILE_ _PCR\_INDEX_

# DESCRIPTION

**tpm2_pcrevent**(1) - Hashes _FILE_ if specified or stdin. It uses all of the
hashing algorithms that the TPM supports.

Optionally, if a PCR index is specified, it extends that PCR for all
supported algorithms with the hash digest. _FILE_ and _PCR\_INDEX\_ arguments
don't need to come in any particular order.

In either case, it
outputs to stdout the hash algorithm used and the digest value,
one per line:

_alg_:_digest_

Where _alg_ is the algorithm used (like sha1) and _digest_ is the digest
resulting from the hash computation of _alg_ on the data.

See sections 23.1 and sections 17 of the [TPM2.0 Specification](https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-3-Commands-01.38.pdf)

# OPTIONS

These options control extending the pcr:

  * **-P**, **\--auth**=_AUTH_:

    Specifies the authorization value for PCR.

[common options](common/options.md)

[common tcti options](common/tcti.md)

[authorization formatting](common/authorizations.md)

# EXAMPLES

## Hash a file
```bash
echo "foo" > data
tpm2_pcrevent data
```

## Hash a file and extend PCR 8
```bash
echo "foo" > data
tpm2_pcrevent 8 data
```

[returns](common/returns.md)

[footer](common/footer.md)