Tips for Linux Shell scripts--not updated regularly

This article is intended to accumulate a solution to small problems that are encountered when writing shell scripts at ordinary times. There are occasional updates here for later review and continuation.

One, define the default values in the shell script

1. Assigning values directly to default variables

Read-p "INPUT>>:" Nub

NUB=${NUB:-30}

Echo ${nub}

2. Assigning a variable value to the default variable

Read-p "INPUT>>:" Nub

nub=${nub:-$ (date +%y%m%d)}

Echo ${nub}

Tips for Linux Shell scripts--not updated regularly