CODEWITHSUNDEEP
arraysbashfor-loop
me.at.coding
me.at.coding

Reputation: 17624

Why does this for-loop not process all elements of the array?

Given the following script:

#!/bin/bash

asteriskFiles=("sip.conf" "extensions.conf")

for asteriskFile in $asteriskFiles
do
    # backup current configuration file
    cp somepath/${asteriskFile} test/
    echo "test"
done

This gives me the output "test" only once, so the loop runs only once instead of two times (two entries in asteriskFiles array). What am I doing wrong? Thanks for any hint!

Upvotes: 6

Views: 2916

Answers (3)

Todd A. Jacobs
Todd A. Jacobs

Reputation: 84343

The Probem

The asteriskFiles variable holds an array. If you dereference it like a scalar, you only get the first element of the array.

The Solution

You want to use the correct shell parameter expansion to access all the subscript elements. For example:

$ echo "${asteriskFiles[@]}"
sip.conf extensions.conf

The @ subscript (when correctly quoted) will expand to the properly-tokenized elements of your array, which your for-loop will then be able to iterate over.

Upvotes: 2

Rucent88
Rucent88

Reputation: 950

Write the beginning of your loop like this

for asteriskFile in "${asteriskFiles[@]}"

Upvotes: 2

kojiro
kojiro

Reputation: 77089

An illustration:

$ asteriskFiles=("sip.conf" "extensions.conf")
$ echo $asteriskFiles # is equivalent to echo ${asteriskFiles[0]}
sip.conf
$ echo "${asteriskFiles[@]}"
sip.conf extensions.conf

Note that the quotes are important. echo ${asteriskFiles[@]} might seem to work, but bash would wordsplit on whitespace if any of your files had whitespace in them.

Upvotes: 11

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