This shell case is relatively simple, but it has its own characteristics.
#!/bin/sh # scriptbc - Wrapper for 'bc' that returns the result of a calculation. if [ $1 = "-p" ] ; then precision=$2 shift 2 else precision=2 # default fi bc -q << EOF scale=$precision $* quit EOF exit 0
1) The script as a whole is concise and clear, but it is powerful, and can realize the operation with custom value.
2) Scale = $precision is a parameter passed to BC to display the number of decimal places
scale=$precision $* quit
It is used to pass values to the script, similar to the effect of manual input in bash.
4） precision=$2 ； Shift 2 is an interesting line. With this, you can implement the function of script parameters,
Shift 2 means to shift the input parameter to the left by 2 bits, i.e. $1, clear $2 first, assign $3 to $1 and $4 to $2.