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Shoichi Kaji > App-RemoteCommand-0.95 > App::RemoteCommand::Tutorial

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NAME ^

App::RemoteCommand::Tutorial - tutorial!

TUTORIAL ^

App::RemoteCommand or its frontend rcommand is a simple remote command launcher via ssh. You can use it like ssh command.

Let's say you have 6 hosts:

    www001.example.com, www002.example.com, www003.examle.com,
    www001.example.jp,  www002.example.jp,  www003.examle.jp

and you can ssh these hosts without password or passphrase. If your ssh private key needs a passphrase, please setup ssh-agent first.

1. simple

The usual form is (much like ssh command):

    > rcommand HOSTS COMMANDS

For example, to execute uname command in www001.example.com:

    > rcommand www001.example.com uname
    [www001.example.com] Linux
    SUCCESS www001.example.com

Add www002.example.com too:

    > rcommand 'www001.example.com,www002.example.com' uname
    [www001.example.com] Linux
    [www002.example.com] Linux
    SUCCESS www001.example.com
    SUCCESS www002.example.com

Oh, you can use range notation [*-*] instead of using just separator ,:

    > rcommand 'www[001-003].example.com' uname
    [www001.example.com] Linux
    [www002.example.com] Linux
    [www003.example.com] Linux
    SUCCESS www001.example.com
    SUCCESS www002.example.com
    SUCCESS www003.example.com

and choice notation {*,*}:

    > rcommand 'www001.example.{com,jp}' uname
    [www001.example.com] Linux
    [www001.example.jp] Linux
    SUCCESS www001.example.com
    SUCCESS www001.example.jp

of course both at the same time:

    > rcommand 'www00[1-2].example.{com,jp}' uname
    [www001.example.com] Linux
    [www002.example.com] Linux
    [www001.example.jp] Linux
    [www002.example.jp] Linux
    SUCCESS www001.example.com
    SUCCESS www002.example.com
    SUCCESS www001.example.jp
    SUCCESS www002.example.jp
2. execute local script

Sometimes it is hard to write command in one liner. Why don't you write a script in local and execute it with rcommand :

    > cat local-script.sh
    #!/bin/bash
    percent=`df -h | grep /dev/sda1 | perl -anle '$F[-2] =~ s/%//; print $F[-2]'`
    if [ $percent -lt 80 ]; then
      echo "OK $percent%"
    else
      echo "NG $percent%"; exit 1
    fi

    > rcommand --script local-script.sh 'www00[1-2].example.jp'
    [www002.example.jp] OK 65%
    [www001.example.jp] NG 85%
    FAIL www001.example.jp
    SUCCESS www002.example.jp

Note that the SUCCESS/FAIL summary is displayed in the end.

3. sudo password

If you want to run command which includes sudo command, please execute rcommand with --ask-sudo-password option:

    > rcommand --ask-sudo-password 'www00[1-2].example.jp' sudo service cron restart
    sudo password (asking with rcommand):
    [www002.example.jp] sudo password (asking with rcommand):
    [www002.example.jp]
    [www001.example.jp] sudo password (asking with rcommand):
    [www001.example.jp]
    [www002.example.jp] cron stop/waiting
    [www002.example.jp] cron start/running, process 7416
    ...
4. misc

You can specify target hosts by host file with --host-file option:

    > cat host.txt
    # comment
    www001.example.jp
    www002.example.com

    > rcommand --host-file host.txt 'w | head -n1'
    [www002.example.com]  15:35:11 up  2:00,  1 user,  load average: 0.00, 0.01, 0.05
    [www001.example.jp]  15:35:12 up  2:00,  2 users,  load average: 0.03, 0.03, 0.05
    ...

You can append current time to each output line with --append-time option:

    > rcommand --append-time www001.example.jp 'echo 1; sleep 1; echo 2'
    [2015-01-05 00:36:58][www001.example.jp] 1
    [2015-01-05 00:36:59][www001.example.jp] 2
    ...

You can remove hostname in each output line with --no-append-hostname option:

    > rcommand --no-append-hostname www001.example.jp 'uname -a'
    Linux vagrant-ubuntu-trusty-64 3.13.0-30-generic #55-Ubuntu SMP Fri Jul 4 21:40:53 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
    SUCCESS www001.example.jp

By default, rcommand execute command in 5 parallel. You can change it with --concurrency option:

    > rcommand --concurrency 1 -a 'www00[1-3].example.{jp,com}' sudo service httpd stop
    ...
5. help

Please type:

    > rcommand --help
syntax highlighting: