Iterate over a specific command line parameter-CodePudding

I have a script with multiple command line parameters and I'd like to use one of them in a for loop. Here is a simplified version:

while getopts s:p: flag
do
    case "${flag}" in
        s) samples=${OPTARG};;
        p) parameter=${OPTARG};;
    esac
done

for sample in $samples
do

    echo "$sample" echo "$parameter"

done

When I run bash script.sh -s Sample1 Sample2 Sample3 -p test I get:

Sample1 echo

But what I would like to get is:

Sample1 test
Sample2 test
Sample3 test

How would I go about this? I only see info for iterating through all the command line parameters using $@ but I don't know how to iterate through a specific command line parameter. Thanks in advance!

CodePudding user response：

You need to provide -s multiple times and append the values (or use an array)

#!/bin/bash

while getopts s:p: flag
do
    case "${flag}" in
        s) samples ="${OPTARG} ";;
        p) parameter=${OPTARG};;
        *) exit 1;;
    esac
done

for sample in $samples
do
    echo "$sample" "$parameter"

done

result:

./script.sh -s Sample1 -s Sample2 -s Sample3 -p test
Sample1 test
Sample2 test
Sample3 test

CodePudding user response：

For the use case when one of the parameters is taking multiple arguments (and assuming you can modify the calling sequence) consider:

Script.sh -p test —- Sample1 Sample2 Sample3

While can be parse using modified version of your code. The advantage is that it’s easier to use with other linux tools. E.g.

 Script.sh -p test Sample*    # if samples are files

Script will be


while getopts p: flag
do
    case "${flag}" in
        p) parameter=${OPTARG};;
    esac
done
shift $((OPTIND-1))  # remove options for argument list

for sample ; do

    echo "$sample" ; echo "$parameter"

done