anchor.diff:  [[help]]
   === Help
   
  -Each of the commands accepts a query string parameter `h` which will
  +Each of the commands accepts a query string parameter `help` which will
   output its available columns.
   
   [source,shell]
   --------------------------------------------------
  -% curl 'localhost:9200/_cat/master?h'
  +% curl 'localhost:9200/_cat/master?help'
   id   | node id
   ip   | node transport ip address
   node | node name
  
positive.code: [[headers]]
  === Headers
  
  Each of the commands accepts a query string parameter `h` which will
  output its available columns.
  
  [source,shell]
  --------------------------------------------------
  % curl 'n1:9200/_cat/nodes?headers=ip,port,heapPercent,name'
  192.168.56.40 9300 40.3 Captain Universe
  192.168.56.20 9300 15.3 Kaluu
  192.168.56.50 9300 17.0 Yellowjacket
  
negative.code: when looking at an ssh terminal, need compact and aligned text.  The
  cat API aims to meet this need.
  
  All the cat commands accept a query string parameter `help` to see all
  the headers and info they provide, and the `/_cat?help` command lists all
  the available commands.
  
  [float]
  