mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-24 06:56:14 +02:00
eb7d7780b1
This is needed to avoid this https://github.com/mesonbuild/meson/issues/13774 when we go back to making our subproject directory `src`.
154 lines
4.5 KiB
Markdown
154 lines
4.5 KiB
Markdown
# Name
|
||
|
||
`nix-hash` - compute the cryptographic hash of a path
|
||
|
||
# Synopsis
|
||
|
||
`nix-hash` [`--flat`] [`--base32`] [`--truncate`] [`--type` *hashAlgo*] *path…*
|
||
|
||
`nix-hash` [`--to-base16`|`--to-base32`|`--to-base64`|`--to-sri`] [`--type` *hashAlgo*] *hash…*
|
||
|
||
# Description
|
||
|
||
The command `nix-hash` computes the cryptographic hash of the contents
|
||
of each *path* and prints it on standard output. By default, it computes
|
||
an MD5 hash, but other hash algorithms are available as well. The hash
|
||
is printed in hexadecimal. To generate the same hash as
|
||
`nix-prefetch-url` you have to specify multiple arguments, see below for
|
||
an example.
|
||
|
||
The hash is computed over a *serialisation* of each path: a dump of
|
||
the file system tree rooted at the path. This allows directories and
|
||
symlinks to be hashed as well as regular files. The dump is in the
|
||
*[Nix Archive (NAR)][Nix Archive] format* produced by [`nix-store
|
||
--dump`](@docroot@/command-ref/nix-store/dump.md). Thus, `nix-hash path`
|
||
yields the same cryptographic hash as `nix-store --dump path |
|
||
md5sum`.
|
||
|
||
[Nix Archive]: @docroot@/store/file-system-object/content-address.md#serial-nix-archive
|
||
|
||
# Options
|
||
|
||
- `--flat`
|
||
|
||
Print the cryptographic hash of the contents of each regular file *path*.
|
||
That is, instead of computing
|
||
the hash of the [Nix Archive (NAR)](@docroot@/store/file-system-object/content-address.md#serial-nix-archive) of *path*,
|
||
just [directly hash]((@docroot@/store/file-system-object/content-address.md#serial-flat) *path* as is.
|
||
This requires *path* to resolve to a regular file rather than directory.
|
||
The result is identical to that produced by the GNU commands
|
||
`md5sum` and `sha1sum`.
|
||
|
||
- `--base16`
|
||
|
||
Print the hash in a hexadecimal representation (default).
|
||
|
||
- `--base32`
|
||
|
||
Print the hash in a base-32 representation rather than hexadecimal.
|
||
This base-32 representation is more compact and can be used in Nix
|
||
expressions (such as in calls to `fetchurl`).
|
||
|
||
- `--base64`
|
||
|
||
Similar to --base32, but print the hash in a base-64 representation,
|
||
which is more compact than the base-32 one.
|
||
|
||
- `--sri`
|
||
|
||
Print the hash in SRI format with base-64 encoding.
|
||
The type of hash algorithm will be prepended to the hash string,
|
||
followed by a hyphen (-) and the base-64 hash body.
|
||
|
||
- `--truncate`
|
||
|
||
Truncate hashes longer than 160 bits (such as SHA-256) to 160 bits.
|
||
|
||
- `--type` *hashAlgo*
|
||
|
||
Use the specified cryptographic hash algorithm, which can be one of
|
||
`md5`, `sha1`, `sha256`, and `sha512`.
|
||
|
||
- `--to-base16`
|
||
|
||
Don’t hash anything, but convert the base-32 hash representation
|
||
*hash* to hexadecimal.
|
||
|
||
- `--to-base32`
|
||
|
||
Don’t hash anything, but convert the hexadecimal hash representation
|
||
*hash* to base-32.
|
||
|
||
- `--to-base64`
|
||
|
||
Don’t hash anything, but convert the hexadecimal hash representation
|
||
*hash* to base-64.
|
||
|
||
- `--to-sri`
|
||
|
||
Don’t hash anything, but convert the hexadecimal hash representation
|
||
*hash* to SRI.
|
||
|
||
# Examples
|
||
|
||
Computing the same hash as `nix-prefetch-url`:
|
||
|
||
```console
|
||
$ nix-prefetch-url file://<(echo test)
|
||
1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
|
||
$ nix-hash --type sha256 --flat --base32 <(echo test)
|
||
1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
|
||
```
|
||
|
||
Computing hashes:
|
||
|
||
```console
|
||
$ mkdir test
|
||
$ echo "hello" > test/world
|
||
|
||
$ nix-hash test/ (MD5 hash; default)
|
||
8179d3caeff1869b5ba1744e5a245c04
|
||
|
||
$ nix-store --dump test/ | md5sum (for comparison)
|
||
8179d3caeff1869b5ba1744e5a245c04 -
|
||
|
||
$ nix-hash --type sha1 test/
|
||
e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
|
||
$ nix-hash --type sha1 --base16 test/
|
||
e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
|
||
$ nix-hash --type sha1 --base32 test/
|
||
nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
|
||
|
||
$ nix-hash --type sha1 --base64 test/
|
||
5P2Lpfe76upazon+ECVVNs1g2rY=
|
||
|
||
$ nix-hash --type sha1 --sri test/
|
||
sha1-5P2Lpfe76upazon+ECVVNs1g2rY=
|
||
|
||
$ nix-hash --type sha256 --flat test/
|
||
error: reading file `test/': Is a directory
|
||
|
||
$ nix-hash --type sha256 --flat test/world
|
||
5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03
|
||
```
|
||
|
||
Converting between hexadecimal, base-32, base-64, and SRI:
|
||
|
||
```console
|
||
$ nix-hash --type sha1 --to-base32 e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
|
||
|
||
$ nix-hash --type sha1 --to-base16 nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
|
||
e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
|
||
$ nix-hash --type sha1 --to-base64 e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
5P2Lpfe76upazon+ECVVNs1g2rY=
|
||
|
||
$ nix-hash --type sha1 --to-sri nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
|
||
sha1-5P2Lpfe76upazon+ECVVNs1g2rY=
|
||
|
||
$ nix-hash --to-base16 sha1-5P2Lpfe76upazon+ECVVNs1g2rY=
|
||
e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
|
||
```
|