Bash Array Accessing with File Globs

Question

I am very new to bash scripting but am having trouble accessing an array. (or what I believe to be an array) I am using a file glob to get the contents of an array.

I simply want to print each file and then allow the user to pick one based on its index. However I am noticing that everything is stored in the first element of the array. What am I missing? Is file globbing not the best idea here for what I want?

files=templates/*.tex
fnum=0
for file in $files
do
        echo $fnum : $file
        # bash expression is ((expression)) $(( expression )) expects a command
        (( fnum++ ))
done
read -p "Which file would you like to include: " answer
if [ $answer -ge 0 ] && [ $answer -lt $fnum ]
then
        echo ${$files[0]}
else
        echo bad range...
        exit 1
fi

Aside: There are a lot of bugs in here that shellcheck.net would find automatically. — Charles Duffy
– Charles Duffy, Commented Jul 28, 2015 at 17:59

chepner · Accepted Answer · 2015-07-28 18:08:05Z

7

files is not an array; files=( templates/*.tex ) is.

files=( templates/*.tex )
fnum=0
for file in "${files[@]}"
do
        echo "$fnum : $file"
        (( fnum++ ))
done
read -p "Which file would you like to include: " answer
if [ "$answer" -ge 0 ] && [ "$answer" -lt "$fnum" ]
then
        echo "${files[answer]}"
else
        echo bad range...
        exit 1
fi

More idiomatically in bash (not identical, but provides the same basic functionality much more concisely):

PS3="Which file would you like to include: "
select answer in "${files[@]}"; do
    echo "$answer"
    break
done

edited Jul 28, 2015 at 18:08

answered Jul 28, 2015 at 17:39

chepner

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7 Comments

chepner Over a year ago

As an aside, you can get rid of fnum, the read command, and the range check using the select command in bash.

9er Over a year ago

"${files[@]} what does this mean?

9er Over a year ago

also for the ${$files[answer]} line it is saying its a bad substitution. $answer gets the same result

Charles Duffy Over a year ago

@9er, ${files[$answer]} is the correct way to write that.

Charles Duffy Over a year ago

@chepner, ...btw, you have rather a lot of quoting bugs here. Mind if I step in and fix them up?

|

switch87 · Accepted Answer · 2015-07-28 17:46:34Z

1

Your files variable is a string, try files=( templates/*.tex ) if I am not mistaking this should make an array of the files

To iterate over the array you should use for file in "${files[@]}"

edited Jul 28, 2015 at 17:46

answered Jul 28, 2015 at 17:40

switch87

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