yadm/yadm.1

.\" vim: set spell so=8:
.TH yadm 1 "17 December 2019" "2.3.0"

.SH NAME

yadm \- Yet Another Dotfiles Manager

.SH SYNOPSIS

.B yadm
.I command
.RI [ options ]

.B yadm
.I git-command-or-alias
.RI [ options ]

.B yadm
init
.RB [ -f ]
.RB [ -w
.IR dir ]

.B yadm
.RI clone " url
.RB [ -f ]
.RB [ -w
.IR dir ]
.RB [ -b
.IR branch ]
.RB [ --bootstrap ]
.RB [ --no-bootstrap ]

.B yadm
.RI config " name
.RI [ value ]

.B yadm
config
.RB [ -e ]

.B yadm
list
.RB [ -a ]

.BR yadm " bootstrap

.BR yadm " encrypt

.BR yadm " decrypt
.RB [ -l ]

.BR yadm " alt

.BR yadm " perms

.BR yadm " enter [ command ]

.BR yadm " git-crypt [ options ]

.BR yadm " upgrade

.BR yadm " introspect
.I category

.SH DESCRIPTION

yadm is a tool for managing a collection of files across multiple computers,
using a shared Git repository.
In addition, yadm provides a feature to select alternate versions of files for
particular systems.
Lastly, yadm supplies the ability to manage a subset of secure files, which are
encrypted before they are included in the repository.

.SH COMMANDS

.TP
.IR git-command " or " git-alias
Any command not internally handled by yadm is passed through to
.BR git (1).
Git commands or aliases are invoked with the yadm managed repository.
The working directory for Git commands will be the configured
.IR work-tree " (usually
.IR $HOME ).

Dotfiles are managed by using standard
.B git
commands;
.IR add ,
.IR commit ,
.IR push ,
.IR pull ,
etc.

.RI The " config
command is not passed directly through.
Instead use the
.I gitconfig
command (see below).
.TP
.B alt
Create symbolic links and process templates for any managed files matching the
naming rules described in the ALTERNATES and TEMPLATES sections. It is usually
unnecessary to run this command, as yadm automatically processes alternates by
default. This automatic behavior can be disabled by setting the configuration
.I yadm.auto-alt
to "false".
.TP
.B bootstrap
Execute
.I $HOME/.config/yadm/bootstrap
if it exists.
.TP
.BI clone " url
Clone a remote repository for tracking dotfiles.
After the contents of the remote repository have been fetched, a "merge" of
.I origin/master
is attempted.
If there are conflicting files already present in the
.IR work-tree ,
this merge will fail and instead a "reset" of
.I origin/master
will be done, followed by a "stash". This "stash" operation will preserve the
original data.

You can review the stashed conflicts by running the command

.RS
.RS
yadm stash show -p
.RE

from within your
.I $HOME
directory. If you want to restore the stashed data, you can run

.RS
yadm stash apply
.RE
or
.RS
yadm stash pop
.RE

The repository is stored in
.IR $HOME/.config/yadm/repo.git .
By default,
.I $HOME
will be used as the
.IR work-tree ,
but this can be overridden with the
.BR -w " option.
yadm can be forced to overwrite an existing repository by providing the
.BR -f " option.
If you want to use a branch other than
.IR origin/master ,
you can specify it using the
.BR -b " option.
By default yadm will ask the user if the bootstrap program should be run (if it
exists). The options
.BR --bootstrap " or " --no-bootstrap
will either force the bootstrap to be run, or prevent it from being run,
without prompting the user.
.RE
.TP
.B config
This command manages configurations for yadm.
This command works exactly they way
.BR git-config (1)
does.
See the CONFIGURATION section for more details.
.TP
.B decrypt
Decrypt all files stored in
.IR $HOME/.config/yadm/files.gpg .
Files decrypted will be relative to the configured
.IR work-tree " (usually
.IR $HOME ).
Using the
.B -l
option will list the files stored without extracting them.
.TP
.B encrypt
Encrypt all files matching the patterns found in
.IR $HOME/.config/yadm/encrypt .
See the ENCRYPTION section for more details.
.TP
.B enter
Run a sub-shell with all Git variables set. Exit the sub-shell the same way you
leave your normal shell (usually with the "exit" command). This sub-shell can
be used to easily interact with your yadm repository using "git" commands. This
could be useful if you are using a tool which uses Git directly, such as tig,
vim-fugitive, git-cola, etc.

Optionally, you can provide a command after "enter", and instead of invoking
your shell, that command will be run with all of the Git variables exposed to
the command's environment.

Emacs Tramp and Magit can manage files by using this configuration:

.RS
    (add-to-list 'tramp-methods
         '("yadm"
           (tramp-login-program "yadm")
           (tramp-login-args (("enter")))
           (tramp-login-env (("SHELL") ("/bin/sh")))
           (tramp-remote-shell "/bin/sh")
           (tramp-remote-shell-args ("-c"))))
.RE

.RS
With this config, use (magit-status "/yadm::"). If you find issue with Emacs 27 and zsh,
trying running (setenv "SHELL" "/bin/bash").
.RE
.TP
.BI git-crypt " options
If git-crypt is installed, this command allows you to pass options directly to
git-crypt, with the environment configured to use the yadm repository.

git-crypt enables transparent encryption and decryption of files in a git repository.
You can read
https://github.com/AGWA/git-crypt
for details.
.TP
.B gitconfig
Pass options to the
.B git config
command. Since yadm already uses the
.I config
command to manage its own configurations,
this command is provided as a way to change configurations of the repository
managed by yadm.
One useful case might be to configure the repository so untracked files are
shown in status commands. yadm initially configures its repository so that
untracked files are not shown.
If you wish use the default Git behavior (to show untracked files and
directories), you can remove this configuration.

.RS
.RS
yadm gitconfig --unset status.showUntrackedFiles
.RE
.RE
.TP
.B help
Print a summary of yadm commands.
.TP
.B init
Initialize a new, empty repository for tracking dotfiles.
The repository is stored in
.IR $HOME/.config/yadm/repo.git .
By default,
.I $HOME
will be used as the
.IR work-tree ,
but this can be overridden with the
.BR -w " option.
yadm can be forced to overwrite an existing repository by providing the
.BR -f " option.
.TP
.B list
Print a list of files managed by yadm.
.RB The " -a
option will cause all managed files to be listed.
Otherwise, the list will only include files from the current directory or below.
.TP
.BI introspect " category
Report internal yadm data. Supported categories are
.IR commands ,
.IR configs ,
.IR repo,
and
.IR switches .
The purpose of introspection is to support command line completion.
.TP
.B perms
Update permissions as described in the PERMISSIONS section.
It is usually unnecessary to run this command, as yadm automatically processes
permissions by default. This automatic behavior can be disabled by setting the
configuration
.I yadm.auto-perms
to "false".
.TP
.B upgrade
Version 2 of yadm uses a different directory for storing your configurations.
When you start to use version 2 for the first time, you may see warnings about
moving your data to this new directory.
The easiest way to accomplish this is by running "yadm upgrade".
This command will start by moving your yadm repo to the new path.
Next it will move any configuration data to the new path.
If the configurations are tracked within your yadm repo, this command will
"stage" the renaming of those files in the repo's index.
Upgrading will also re-initialize all submodules you have added (otherwise they
will be broken when the repo moves).
After running "yadm upgrade", you should run "yadm status" to review changes
which have been staged, and commit them to your repository.

You can read
https://yadm.io/docs/upgrade_from_1
for more information.
.TP
.B version
Print the version of yadm.

.SH COMPATIBILITY

Beginning with version 2.0.0, yadm introduced a couple major changes which may
require you to adjust your configurations.
See the
.B upgrade
command for help making those adjustments.

First, yadm now uses the "XDG Base Directory Specification" to find its
configurations. You can read
https://yadm.io/docs/upgrade_from_1
for more information.

Second, the naming conventions for alternate files have been changed.
You can read https://yadm.io/docs/alternates for more information.

If you want to retain the old functionality, you can set an environment variable,
.IR YADM_COMPATIBILITY=1 .
Doing so will automatically use the old yadm directory, and process alternates
the same as the pre-2.0.0 version. This compatibility mode is deprecated, and
will be removed in future versions. This mode exists solely for transitioning
to the new paths and naming of alternates.

.SH OPTIONS

yadm supports a set of universal options that alter the paths it uses. The
default paths are documented in the FILES section. Any path specified by these
options must be fully qualified. If you always want to override one or more of
these paths, it may be useful to create an alias for the yadm command.
For example, the following alias could be used to override the repository
directory.

.RS
alias yadm='yadm --yadm-repo /alternate/path/to/repo'
.RE

The following is the full list of universal options.
Each option should be followed by a fully qualified path.
.TP
.B -Y,--yadm-dir
Override the yadm directory.
yadm stores its data relative to this directory.
.TP
.B --yadm-repo
Override the location of the yadm repository.
.TP
.B --yadm-config
Override the location of the yadm configuration file.
.TP
.B --yadm-encrypt
Override the location of the yadm encryption configuration.
.TP
.B --yadm-archive
Override the location of the yadm encrypted files archive.
.TP
.B --yadm-bootstrap
Override the location of the yadm bootstrap program.

.SH CONFIGURATION

yadm uses a configuration file named
.IR $HOME/.config/yadm/config .
This file uses the same format as
.BR git-config (1).
Also, you can control the contents of the configuration file
via the
.B yadm config
command (which works exactly like
.BR git-config ).
For example, to disable alternates you can run the command:

.RS
yadm config yadm.auto-alt false
.RE

The following is the full list of supported configurations:
.TP
.B yadm.alt-copy
If set to "true", alternate files will be copies instead of symbolic links.
This might be desirable, because some systems may not properly support
symlinks.

NOTE: The deprecated
.I yadm.cygwin-copy
option used by older versions of yadm has been replaced by
.IR yadm.alt-copy .
The old option will be removed in the next version of yadm.
.TP
.B yadm.auto-alt
Disable the automatic linking described in the section ALTERNATES. If disabled,
you may still run "yadm alt" manually to create the alternate links. This
feature is enabled by default.
.TP
.B yadm.auto-exclude
Disable the automatic exclusion of patterns defined in
.IR $HOME/.config/yadm/encrypt .
This feature is enabled by default.
.TP
.B yadm.auto-perms
Disable the automatic permission changes described in the section PERMISSIONS.
If disabled, you may still run
.B yadm perms
manually to update permissions.
This feature is enabled by default.
.TP
.B yadm.auto-private-dirs
Disable the automatic creating of private directories described in the section PERMISSIONS.
.TP
.B yadm.git-program
Specify an alternate program to use instead of "git".
By default, the first "git" found in $PATH is used.
.TP
.B yadm.gpg-perms
Disable the permission changes to
.IR $HOME/.gnupg/* .
This feature is enabled by default.
.TP
.B yadm.gpg-program
Specify an alternate program to use instead of "gpg".
By default, the first "gpg" found in $PATH is used.
.TP
.B yadm.gpg-recipient
Asymmetrically encrypt files with a gpg public/private key pair.
Provide a "key ID" to specify which public key to encrypt with.
The key must exist in your public keyrings.
If left blank or not provided, symmetric encryption is used instead.
If set to "ASK", gpg will interactively ask for recipients.
See the ENCRYPTION section for more details.
This feature is disabled by default.
.TP
.B yadm.ssh-perms
Disable the permission changes to
.IR $HOME/.ssh/* .
This feature is enabled by default.

.RE
The following four "local" configurations are not stored in the
.IR $HOME/.config/yadm/config,
they are stored in the local repository.

.TP
.B local.class
Specify a class for the purpose of symlinking alternate files.
By default, no class will be matched.
.TP
.B local.hostname
Override the hostname for the purpose of symlinking alternate files.
.TP
.B local.os
Override the OS for the purpose of symlinking alternate files.
.TP
.B local.user
Override the user for the purpose of symlinking alternate files.

.SH ALTERNATES

When managing a set of files across different systems, it can be useful to have
an automated way of choosing an alternate version of a file for a different
operating system, host, user, etc.

yadm will automatically create a symbolic link to the appropriate version of a
file, when a valid suffix is appended to the filename. The suffix contains
the conditions that must be met for that file to be used.

The suffix begins with "##", followed by any number of conditions separated by
commas.

  ##<condition>[,<condition>,...]

Each condition is an attribute/value pair, separated by a period. Some
conditions do not require a "value", and in that case, the period and value can
be omitted. Most attributes can be abbreviated as a single letter.

  <attribute>[.<value>]

These are the supported attributes, in the order of the weighted precedence:

.TP
.BR template , " t
Valid when the value matches a supported template processor.
See the TEMPLATES section for more details.
.TP
.BR user ,  " u
Valid if the value matches the current user.
Current user is calculated by running
.BR "id -u -n" .
.TP
.BR distro , " d
Valid if the value matches the distro.
Distro is calculated by running
.B "lsb_release -si"
or by inspecting the ID from
.BR "/etc/os-release" .
.TP
.BR os , " o
Valid if the value matches the OS.
OS is calculated by running
.BR "uname -s" .
.TP
.BR class , " c
Valid if the value matches the
.B local.class
configuration.
Class must be manually set using
.BR "yadm config local.class <class>" .
See the CONFIGURATION section for more details about setting
.BR local.class .
.TP
.BR hostname , " h
Valid if the value matches the short hostname.
Hostname is calculated by running
.BR "uname -n" ,
and trimming off any domain.
.TP
.B default
Valid when no other alternate is valid.
.LP

.BR NOTE :
The OS for "Windows Subsystem for Linux" is reported as "WSL", even
though uname identifies as "Linux".

You may use any number of conditions, in any order.
An alternate will only be used if ALL conditions are valid.
For all files managed by yadm's repository or listed in
.IR $HOME/.config/yadm/encrypt ,
if they match this naming convention,
symbolic links will be created for the most appropriate version.

The "most appropriate" version is determined by calculating a score for each
version of a file. A template is always scored higher than any symlink
condition. The number of conditions is the next largest factor in scoring.
Files with more conditions will always be favored. Any invalid condition will
disqualify that file completely.

If you don't care to have all versions of alternates stored in the same
directory as the generated symlink, you can place them in the
.I $HOME/.config/yadm/alt
directory. The generated symlink or processed template will be created using
the same relative path.

Alternate linking may best be demonstrated by example. Assume the following
files are managed by yadm's repository:

  - $HOME/path/example.txt##default
  - $HOME/path/example.txt##class.Work
  - $HOME/path/example.txt##os.Darwin
  - $HOME/path/example.txt##os.Darwin,hostname.host1
  - $HOME/path/example.txt##os.Darwin,hostname.host2
  - $HOME/path/example.txt##os.Linux
  - $HOME/path/example.txt##os.Linux,hostname.host1
  - $HOME/path/example.txt##os.Linux,hostname.host2

If running on a Macbook named "host2",
yadm will create a symbolic link which looks like this:

.IR $HOME/path/example.txt " -> " $HOME/path/example.txt##os.Darwin,hostname.host2

However, on another Mackbook named "host3", yadm will create a symbolic link
which looks like this:

.IR $HOME/path/example.txt " -> " $HOME/path/example.txt##os.Darwin

Since the hostname doesn't match any of the managed files, the more generic version is chosen.

If running on a Linux server named "host4", the link will be:

.IR $HOME/path/example.txt " -> " $HOME/path/example.txt##os.Linux

If running on a Solaris server, the link will use the default version:

.IR $HOME/path/example.txt " -> " $HOME/path/example.txt##default

If running on a system, with class set to "Work", the link will be:

.IR $HOME/path/example.txt " -> " $HOME/path/example.txt##class.Work

If no "##default" version exists and no files have valid conditions, then no
link will be created.

Links are also created for directories named this way, as long as they have at
least one yadm managed file within them.

yadm will automatically create these links by default. This can be disabled
using the
.I yadm.auto-alt
configuration.
Even if disabled, links can be manually created by running
.BR "yadm alt" .

Class is a special value which is stored locally on each host (inside the local
repository). To use alternate symlinks using class, you must set the value of
class using the configuration
.BR local.class .
This is set like any other yadm configuration with the
.B yadm config
command. The following sets the class to be "Work".

  yadm config local.class Work

Similarly, the values of os, hostname, and user can be manually overridden
using the configuration options
.BR local.os ,
.BR local.hostname ,
and
.BR local.user .

.SH TEMPLATES

If a template condition is defined in an alternate file's "##" suffix, and the
necessary dependencies for the template are available, then the file will be
processed to create or overwrite files.

Supported template processors:
.TP
.B default
This is yadm's built-in template processor. This processor is very basic, with
a Jinja-like syntax. The advantage of this processor is that it only depends
upon
.BR awk ,
which is available on most *nix systems. To use this processor,
specify the value of "default" or just leave the value off (e.g. "##template").
.TP
.B j2cli
To use the j2cli Jinja template processor, specify the value of "j2"  or
"j2cli".
.TP
.B envtpl
To use the envtpl Jinja template processor, specify the value of "j2" or "envtpl".
.LP

.BR NOTE :
Specifying "j2" as the processor will attempt to use j2cli or envtpl, whichever
is available.

If the template processor specified is available, templates will be processed
to create or overwrite files.

During processing, the following variables are available in the template:

 Default         Jinja           Description
 -------------   -------------   --------------------------
 yadm.class      YADM_CLASS      Locally defined yadm class
 yadm.distro     YADM_DISTRO     lsb_release -si
 yadm.hostname   YADM_HOSTNAME   uname -n (without domain)
 yadm.os         YADM_OS         uname -s
 yadm.user       YADM_USER       id -u -n
 yadm.source     YADM_SOURCE     Template filename

.BR NOTE :
The OS for "Windows Subsystem for Linux" is reported as "WSL", even
though uname identifies as "Linux".

.BR NOTE :
If lsb_release is not available, DISTRO will be the ID specified in
/etc/os-release.

Examples:

.I whatever##template
with the following content

  {% if yadm.user == 'harvey' %}
  config={{yadm.class}}-{{yadm.os}}
  {% else %}
  config=dev-whatever
  {% endif %}

would output a file named
.I whatever
with the following content if the user is "harvey":

  config=work-Linux

and the following otherwise:

  config=dev-whatever

An equivalent Jinja template named
.I whatever##template.j2
would look like:

  {% if YADM_USER == 'harvey' -%}
  config={{YADM_CLASS}}-{{YADM_OS}}
  {% else -%}
  config=dev-whatever
  {% endif -%}

.SH ENCRYPTION

It can be useful to manage confidential files, like SSH or GPG keys, across
multiple systems. However, doing so would put plain text data into a Git
repository, which often resides on a public system. yadm can make it easy to
encrypt and decrypt a set of files so the encrypted version can be maintained
in the Git repository.
This feature will only work if the
.BR gpg (1)
command is available.

To use this feature, a list of patterns must be created and saved as
.IR $HOME/.config/yadm/encrypt .
This list of patterns should be relative to the configured
.IR work-tree " (usually
.IR $HOME ).
For example:

.RS
    .ssh/*.key
    .gnupg/*.gpg
.RE

Standard filename expansions (*, ?, [) are supported.
If you have Bash version 4, you may use "**" to match all subdirectories.
Other shell expansions like brace and tilde are not supported.
Spaces in paths are supported, and should not be quoted.
If a directory is specified, its contents will be included, but not recursively.
Paths beginning with a "!" will be excluded.

The
.B yadm encrypt
command will find all files matching the patterns, and prompt for a password. Once a
password has confirmed, the matching files will be encrypted and saved as
.IR $HOME/.config/yadm/files.gpg .
The patterns and files.gpg should be added to the yadm repository so they are
available across multiple systems.

To decrypt these files later, or on another system run
.B yadm decrypt
and provide the correct password.
After files are decrypted, permissions are automatically updated as described
in the PERMISSIONS section.

Symmetric encryption is used by default, but asymmetric encryption may be
enabled using the
.I yadm.gpg-recipient
configuration.

.BR NOTE :
It is recommended that you use a private repository when keeping confidential
files, even though they are encrypted.

Patterns found in
.I $HOME/.config/yadm/encrypt
are automatically added to the repository's
.I info/exclude
file every time
.B yadm encrypt
is run.
This is to prevent accidentally committing sensitive data to the repository.
This can be disabled using the
.I yadm.auto-exclude
configuration.

.B Using git-crypt

A completely separate option for encrypting data is to install and use git-crypt.
Once installed, you can run git-crypt commands for the yadm repo by running
.BR "yadm git-crypt" .
git-crypt enables transparent encryption and decryption of files in a git repository.
You can read
https://github.com/AGWA/git-crypt
for details.
.LP

.SH PERMISSIONS

When files are checked out of a Git repository, their initial permissions are
dependent upon the user's umask. Because of this, yadm will automatically
update the permissions of some file paths. The "group" and "others" permissions
will be removed from the following files:

.RI - " $HOME/.config/yadm/files.gpg

- All files matching patterns in
.I $HOME/.config/yadm/encrypt

- The SSH directory and files,
.I .ssh/*

- The GPG directory and files,
.I .gnupg/*

yadm will automatically update permissions by default. This can be disabled
using the
.I yadm.auto-perms
configuration. Even if disabled, permissions can be manually updated by running
.BR "yadm perms" .
The
.I .ssh
directory processing can be disabled using the
.I yadm.ssh-perms
configuration. The
.I .gnupg
directory processing can be disabled using the
.I yadm.gpg-perms
configuration.

When cloning a repo which includes data in a
.IR .ssh " or " .gnupg
directory, if those directories do not exist at the time of cloning, yadm will
create the directories with mask 0700 prior to merging the fetched data into
the work-tree.

When running a Git command and
.IR .ssh " or " .gnupg
directories do not exist, yadm will create those directories with mask 0700
prior to running the Git command. This can be disabled using the
.I yadm.auto-private-dirs
configuration.

.SH HOOKS

For every command yadm supports, a program can be provided to run before or
after that command. These are referred to as "hooks". yadm looks for hooks in
the directory
.IR $HOME/.config/yadm/hooks .
Each hook is named using a prefix of
.I pre_
or
.IR post_ ,
followed by the command which should trigger the hook. For
example, to create a hook which is run after every
.I yadm pull
command, create a hook named
.IR post_pull.
Hooks must have the executable file permission set.

If a
.I pre_
hook is defined, and the hook terminates with a non-zero exit status, yadm will
refuse to run the yadm command. For example, if a
.I pre_commit
hook is defined, but that command ends with a non-zero exit status, the
.I yadm commit
will never be run. This allows one to "short-circuit" any operation using a
.I pre_
hook.

Hooks have the following environment variables available to them at runtime:
.TP
.B YADM_HOOK_COMMAND
The command which triggered the hook
.TP
.B YADM_HOOK_EXIT
The exit status of the yadm command
.TP
.B YADM_HOOK_FULL_COMMAND
The yadm command with all command line arguments
.TP
.B YADM_HOOK_REPO
The path to the yadm repository
.TP
.B YADM_HOOK_WORK
The path to the work-tree

.SH FILES

All of yadm's configurations are relative to the "yadm directory".
yadm uses the "XDG Base Directory Specification" to determine this directory.
If the environment variable
.B $XDG_CONFIG_HOME
is defined as a fully qualified path, this directory will be
.IR "$XDG_CONFIG_HOME/yadm" .
Otherwise it will be
.IR "$HOME/.config/yadm" .

The following are the default paths yadm uses for its own data.
Most of these paths can be altered using universal options.
See the OPTIONS section for details.
.TP
.I $HOME/.config/yadm
The yadm directory. By default, all data yadm stores is relative to this
directory.
.TP
.I $YADM_DIR/config
Configuration file for yadm.
.TP
.I $YADM_DIR/alt
This is a directory to keep "alternate files" without having them side-by-side
with the resulting symlink or processed template. Alternate files placed in
this directory will be created relative to $HOME instead.
.TP
.I $YADM_DIR/repo.git
Git repository used by yadm.
.TP
.I $YADM_DIR/encrypt
List of globs used for encrypt/decrypt
.TP
.I $YADM_DIR/files.gpg
All files encrypted with
.B yadm encrypt
are stored in this file.

.SH EXAMPLES

.TP
.B yadm init
Create an empty repo for managing files
.TP
.B yadm add .bash_profile ; yadm commit
Add
.I .bash_profile
to the Git index and create a new commit
.TP
.B yadm remote add origin <url>
Add a remote origin to an existing repository
.TP
.B yadm push -u origin master
Initial push of master to origin
.TP
.B echo ".ssh/*.key" >> $HOME/.config/yadm/encrypt
Add a new pattern to the list of encrypted files
.TP
.B yadm encrypt ; yadm add ~/.config/yadm/files.gpg ; yadm commit
Commit a new set of encrypted files

.SH REPORTING BUGS

Report issues or create pull requests at GitHub:

https://github.com/TheLocehiliosan/yadm/issues

.SH AUTHOR

Tim Byrne <sultan@locehilios.com>

.SH SEE ALSO

.BR git (1),
.BR gpg (1)

https://yadm.io/