FAQ: Learn Bash Scripting - Aliases


#1

This community-built FAQ covers the “Aliases” exercise from the lesson “Learn Bash Scripting”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Web Development

Learn the Command Line

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#2

Hello. I am trying to find out what I did wrong here. This is a copy of my code. The first line starts at number 1.

#!/bin/bash
first_greeting=“Nice to meet you!”
later_greeting=“How are you?”
greeting_occasion=0
greeting_limit=$1
while [ $greeting_occasion -lt $greeting_limit ]
do
if [ $greeting_occasion -lt 1 ]
then
echo $first_greeting
else
echo later_greeting fi greeting_occasion=((greeting_occasion + 1))
done

When I try to run my code, I keep getting a unary operator expected error on line 6. Please advise on what I’ve done wrong, because I don’t understand it.


#3

If you write

alias greet3="./script.sh 3"

according to describing (!!on command line) and then write greet3 your script will work.
But I don´t understand why script it can´t be start by normal way???
And why
greeting_limit in the script is written in this way

greeting_limit=$1 ???

I hope I will figure out.


#4

I think the $ sign in greeting_limit=$1 tells it to use the first number that is written by the user in the alias (the first input). So if you try to run it just by typing ./script.sh, you get an error because there is no number for it to use for the greeting_limit.

To complete this exercise, type alias greet3=’./script.sh 3’ in the bash terminal (not in script.sh), then type greet3 to run the script using this alias

You can run the script without the alias by typing ./script.sh and then a single number or a list of numbers, and the script will use the first number that you type. For example, if you type ./script.sh 1 2 3 then the script will run and will show you one greeting.

However - I thought that if you change the script.sh to include greeting_limit=$2 instead of $1 then it would use the second number in a list - but it still appears to use the first number. Any ideas anyone?