101 scripts of reading notes No. 4

Today's case is TheCode #! /Bin/sh # validint -- Validatesintegerinput, allowingnegativeintstoo. functionvalidint {# Validatefirstfield. Thentestagainst...

 

 

In today's case, we will judge user input.

The Code

#! /Bin/sh

# Validint -- Validates integer input, allowing negative ints too.

 

Function validint

{

# Validate first field. Then test against min value $2 and/or

# Max value $3 if they are supplied. If they are not supplied, skip these tests.

 

Number = "$1"; min = "$2"; max = "$3"

 

If [-z $ number]; then

Echo "You didn't enter anything. Unacceptable."> & 2; return 1

Fi

 

If ["$ {number % $ {number #?}} "="-"]; Then # is first char A'-'Sign?

Testvalue = "$ {number #?} "# All but first character

Else

Testvalue = "$ number"

Fi

 

Nodigits = "$ (echo $ testvalue | sed's/[[: digit:] // g ')"

 

If [! -Z $ nodigits]; then

Echo "Invalid number format! Only digits, no commas, spaces, etc. "> & 2

Return 1

Fi

 

If [! -Z $ min]; then

If ["$ number"-lt "$ min"]; then

Echo "Your value is too small: smallest acceptable value is $ min"> & 2

Return 1

Fi

Fi

If [! -Z $ max]; then

If ["$ number"-gt "$ max"]; then

Echo "Your value is too big: largest acceptable value is $ max"> & 2

Return 1

Fi

Fi

Return 0

}

 

 

If validint "$1" "$2" "$3"; then

Echo "That input is a valid integer value within your constraints"

Fi

 

 

 

Parsing script:

1) number = "$1"; min = "$2"; max = "$3" indicates three inputs of the user;

2) nodigits = "$ (echo $ testvalue | sed's/[[: digit:] // g')" to test whether all input by the user is a number.

3) if validint "$1" "$2" "$3"; then note that quotation marks are required for "$1" "$2" "$3.

4) The testvalue variable is used to filter negative numbers and test whether all input values are numbers.

5) I felt like I was thinking well.

 

 

 

 

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