LlamaLabs

Instead of typing in the password to decrypt my private SSH key every time I want to ssh to a host I use a program called ssh-agent, which is included in the openssh-clients package in CentOS.
When you run ssh-agent it creates a long-running process that holds decrypted keys and spits out some environment variables that [...]

First, see what’s in the cache:
$ dscacheutil -cachedump
DirectoryService Cache Overview:
AAAA Queries – Disabled (link-local IPv6 addresses)
Buckets Used – 31
Cache Size – 16
Entry count by category:
Group – 2
Host – 11
User – 3
Flush:
$ dscacheutil -flushcache
$
All gone:
$ dscacheutil -cachedump
DirectoryService Cache Overview:
AAAA Queries – Disabled (link-local IPv6 addresses)
Buckets [...]

Here’s another rpm command I can never remember. This lists all installed packages, and sorts the list based on installed size.
rpm -qa –queryformat ‘%{SIZE} %{NAME} %{VENDOR}\n’ | sort -n

The -qa flag specifies that we wish to query all packages. The –queryformat flag specifies how we want each result to be formatted. See below for [...]