Use the knife xargs
subcommand to take patterns from standard input, download as JSON, run a command against the downloaded JSON, and then upload any changes.
This subcommand has the following syntax:
$ knife xargs [PATTERN...] (options)
Note
Review the list of common options available to this (and all) knife subcommands and plugins.
This subcommand has the following options:
-0
NULL
character (\0
) instead of white space as the separator. Default: false
.--chef-repo-path PATH
chef_repo_path
in client.rb.--concurrency
10
.--[no-]diff
--diff
.--dry-run
false
.--[no-]force
--no-force
.-I REPLACE_STRING
, --replace REPLACE_STRING
nil
.-J REPLACE_STRING
, --replace-first REPLACE_STRING
nil
.--local
false
to build or execute against a remote file. Default: false
.-n MAX_ARGS
, --max-args MAX_ARGS
nil
.-p [PATTERN...]
, --pattern [PATTERN...]
nil
.--repo-mode MODE
static
, everything
, or hosted_everything
. Use static
for just roles, environments, cookbooks, and data bags. By default, everything
and hosted_everything
are dynamically selected depending on the server type. Default value: default
.-s LENGTH
, --max-chars LENGTH
nil
.-t
nil
.Note
See knife.rb for more information about how to add certain knife options as settings in the knife.rb file.
The following examples show how to use this knife subcommand:
Find, and then replace data
The following example will go through all nodes on the server, and then replace the word foobar
with baz
:
$ knife xargs --pattern /nodes/* "perl -i -pe 's/foobar/baz'"
Use output of knife list and Perl
The following examples show various ways of listing all nodes on the server, and then using Perl to replace grantmc
with gmc
:
$ knife list 'nodes/*' | knife xargs "perl -i -pe 's/grantmc/gmc'"
or without quotes and the backslash escaped:
$ knife list /nodes/\* | knife xargs "perl -i -pe 's/grantmc/gmc'"
or by using the --pattern
option:
$ knife xargs --pattern '/nodes.*' "perl -i -pe 's/grantmc/gmc'"
View security groups data
The following example shows how to display the content of all groups on the server:
$ knife xargs --pattern '/groups/*' cat
and will return something like:
{ "name": "4bd14db60aasdfb10f525400cdde21", "users": [ "grantmc" ] }{ "name": "62c4e268e15fasdasc525400cd944b", "users": [ "robertf" ] }{ "name": "admins", "users": [ "grantmc", "robertf" ] }{ "name": "billing-admins", "users": [ "dtek" ] }{ "name": "clients", "clients": [ "12345", "67890", ] }{ "name": "users", "users": [ "grantmc" "robertf" "dtek" ], "groups": [ "4bd14db60aasdfb10f525400cdde21", "62c4e268e15fasdasc525400cd944b" ] }
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https://docs-archive.chef.io/release/12-13/knife_xargs.html