There are only two difficult things in Computer Science: cache invalidation and naming things.

stress can be used to imitate high load. nproc

# Returns number of available CPUs.
$ nproc

$ stress --cpu 1 --timeout 120

# Imitate high load on memory, each worker alocated 256 MB of memory
$ stress --vm 5 --timeout 180

• --context=number - show surrounding lines

• -R - recursive inside directory

   $ grep -R pattern .

• --color to hightlight matches, --color=always to pass colorized output through pipe

# output logs of a service started by systemd, -f to follow output
$ journalctl -u service_name -f

Automatically sets up environment user enters a directory containing .envrc file.

export KEY=VALUE

# Encode, -n to avoid new line character
$ echo -n "string" | base64

# Decode
$ base64 <<< "encoded_string"

Common Log Format (CLF):

• <IP Address> <Client Id> <User Id> <Time> <Request> <Status> <Size>
• 127.0.0.1 - swills [13/Nov/2019:14:43:30 -0800] "GET /assets/234 HTTP/1.0" 200 2326

Generate file with exact size

$ sudo dd if=/dev/zero of=/opt/sfw/bigfile bs=1M count=300