Difference between revisions of "Tech Tips"
From kemiko
Line 124: | Line 124: | ||
</li> | </li> | ||
</ul> | </ul> | ||
+ | |||
+ | |||
+ | '''SQL''': | ||
+ | |||
+ | <ul> | ||
+ | <li> | ||
+ | Always use a where clause even if for everything...where 1 or where 1 = 1. This reminds someone editing the code that this query is operating on EVERYTHING. | ||
+ | </li> | ||
+ | <ul> |
Revision as of 21:16, 25 November 2016
Trouble Shooting:
- Start with the basics...like power, network, etc.
General:
- Know the animal before trying to tame
- Some vendors use MB/GB (decimal...1000s) and some use MiB/GiB (binary...1024s)
- Always query before running modification command(s)
- Backup or already have a backup before modifying files
- Learn your editor(s) well...it's functions can save a ton of time
- Always tail -f error logs when developing
Development:
-
Naming
- Avoid spaces.
- Use camelCase.
- Name common items with the common word starting each item.
- Name same item, but numbered with enough padding to sort correctly. ex: if going to at least 10 use 01-10 instead of 1-10.
- Name date by number not name and most general to specific. So they sort correctly. ex: 20161231 instead of Dec31-2016, etc.
- Name using noun first then verb. ex: logCreate, logList, etc.
-
Coding
- Top-down and bottom-up design
- Always add comments
- Line block brackets up vertically
- Happy balance between elegance/complexity and readability/maintainability
- Happy balance between too long and too short variable naming
- Pick a style and stay consistent
- Learn your debugging tool(s)...they can save a ton of time
-
Give some thought to designing your log files.
- Put the date and time in each record
- Format well...XML, JSON, delimited, etc.
- Make sure enough data is included to be helpful
*nix:
- Type "env" in the shell to display all the environment variables
- Use "set -x" to debug shell scripts ("set +x" turns it off)
- Use "set -o vi" to use vi to navigate/modify shell commands ("set +o" turns it off)
-
crontab
- Put number in 09 format to make easier to read, parse and sort
- Always redirect command output somewhere, log file, /dev/null, etc., so it does not fill up your email
SQL:
- Always use a where clause even if for everything...where 1 or where 1 = 1. This reminds someone editing the code that this query is operating on EVERYTHING.