# Using PDSH

Users can run a command across all compute nodes at once using the pdsh command. This can be useful if users want to make a change to all nodes in the research environment - for example, installing a new software package. The pdsh command can take a number of parameters that control how commands are processed; for example:

• pdsh -g all uptime
  • executes the uptime command on available compute and login nodes in the research environment with the gender all
    
    
• pdsh -g nodes 'sudo yum -y install screen'
  • use yum to install the screen package as the root user on all compute nodes with the gender nodes
    
    
• pdsh -g nodes -f 1 df -h /tmp
  • executes the command df -h /tmp on all compute nodes of the research environment with the gender nodes, one at a time (fanout=1)
    
    
• pdsh -w node01,node03 which ldconfig
  • runs the which ldconfig command on two named nodes only

To learn more about genders, read the tutorial.