Databases
StackOverflow2013
Postsdbo
POHow to assign CLI variables from CLI output
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to assign CLI variables from CLI output
    primarykey
    data
    text
    <p>How do you arbitrarily extract output from CLI?</p> <p>In my specific example (but the answer should generically apply to the whole) I'm trying to write a general-purpose deploy/scale script for a NodeJS/MongoDB technology stack ontop of AWS EC2/EBS with standard Ubuntu server OS (12.04). For now, I'm manually creating and attaching the EBS drives through the AWS Dashboard Console, but everything else should happen automatically, without ever having to SSH in and do stupid CLI (though eventually I want to automate the create&amp;attach parts as well).</p> <p>So first, I need to get a list of all the blocks <code>lsblk -l</code> that are EBS drives to mount. Then I need to (on first time conditions) setup MDADM and LVM, however their commands assume that I know the names of the blocks, such as: </p> <pre><code>sudo mdadm --create --verbose /dev/md0 --level=10 --chunk=256 --raid-devices=4 /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4 </code></pre> <p>and so on. This is great and easy... IF I am a human reading through the CLI output from lsblk. But how does one parse/extract and iterate through it dynamically? Somehow I need to do this (pseudo code):</p> <pre><code>$EBS_ARRAY = lsblk -l -list_the_names_of_blocks_not_mounted sudo mdadm --create --verbose /dev/md0 --level=10 --chunk=256 --raid-devices=EBS_ARRAY.length EBS_ARRAY.join(' ') ...rest of my script here... </code></pre> <p>You can obviously see that I am a javascript guy clueless about how to work dynamically with CLI without JSON and non-interactively (scripted). So... How on earth do you arbitrarily extract information out of CLI output, in an automated way, into variables?</p> <p>Thanks.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USEmil Vikström
    1. USmarknadal
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to assign CLI variables from CLI output
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
      singulars
      1. POHow to assign CLI variables from CLI output
      1. This table or related slice is empty.
      1. VTDownMod
    3. VO
      singulars
      1. POHow to assign CLI variables from CLI output
      1. This table or related slice is empty.
      1. VTDownMod
    1. COGenerally, it is not considered a good tone to start a question with a rant. Especially, if you rant against something other people like, and you're about to ask the very same people to help you out.
      singulars
      1. POHow to assign CLI variables from CLI output
      1. USfork0
    2. COBesides, the rest of your script is elsewhere, but not here. And a example of `lsblk` output would help, too
      singulars
      1. POHow to assign CLI variables from CLI output
      1. USfork0
    3. CO1. Part one of your question shows total ignorance in IT. 2. Have you tried googling it? Man 3 popen() would have helped you out.
      singulars
      1. POHow to assign CLI variables from CLI output
      1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload