README.md

A collection of tools that I think should be in every SysAdmin's ~/bin.

sshec2

Look up some info from EC2 and then SSH to whatever made it into an IP address.

Usage:

usage: sshec2 [-h] [-i INSTANCE_ID] [-o SSH_ARGS] [-r REGION]
              [--log-level LOG_LEVEL] [-a ASG]

Wrap SSH in some EC2 info.

optional arguments:
  -h, --help            show this help message and exit
  -i INSTANCE_ID, --instance-id INSTANCE_ID
                        Instance ID to get to.
  -o SSH_ARGS, --ssh-args SSH_ARGS
                        Arguments to pass to SSH.
  -r REGION, --region REGION
                        EC2 region.
  --log-level LOG_LEVEL
                        Logging level.
  -a ASG, --asg ASG     AutoScaling Group to pick an instnace out of.

avg

Spit out the average of a column in a text file

stddev

Spit out the standard deviation of a column in a text file

column-bin

bin the columns of a text file (VERY useful for quick summaries of apache HTTP status codes and the like)

Usage:

 $ cat test.csv	
	log HTTP status: 200 body_size: 1024
	log HTTP status: 200 body_size: 1024
	log HTTP status: 500 body_size: 0
	log HTTP status: 200 body_size: 10000
	log HTTP status: 400 body_size: 10
	log HTTP status: 400 body_size: 10
	log HTTP status: 400 body_size: 10
	log HTTP status: 409 body_size: 10
 $ column-bin -c 4 < test.csv
	409	1
	400	3
	200	3
	500	1

column-histogram

Similar to column-bin, but for continuous variables. Bin the column into bins of a fixed size OR bin them into log-based sizes to make either a histogram or a semi-log histogram.

Usage:

 $ cat test.csv	
	log HTTP status: 200 body_size: 1024
	log HTTP status: 200 body_size: 1024
	log HTTP status: 500 body_size: 0
	log HTTP status: 200 body_size: 10000
	log HTTP status: 400 body_size: 10
	log HTTP status: 400 body_size: 10
	log HTTP status: 400 body_size: 10
	log HTTP status: 409 body_size: 10
 $ column-histogram -c 6 -b 1000 < test.csv
	10000	1
	0	5
	1000	2
 $ column-histogram -c 6 -L 10 < test.csv
	10000	1
	0	1
	10	4
	1000	2

cronlock

Ensure that only one copy of a crontab job is running at a time. This uses a per-user lock directory and checks for presence of a file named after the hash of the parents cmdline plus the current cmdline. If the file exists, the cron job exits quietly and "cleanly" without running the actual job. If the file doesn't exist, it creates the file and executes the job.

Usage:

$ crontab -e
  */10 * * * * cronlock /that/command which-must-only-be-running-once