BASH - find regex in array, print found array items

Question

I have tested the regex here: http://regexr.com/3bchs

I cant get the array to only print the regex search terms.

files=(`ls $BACKUPDIR`)
daterange='(2015\-06\-)[0-9]+\s?'

for i in "${files[@]}"
do
        if [[ "$files[$i]" =~ $daterange ]];
         then
                 echo $i
         fi
done

Input: 2015-06-06 2015-06-13 2015-06-20 2015-06-27 2015-07-04 2015-07-11

Output:

You can try to execute your script with bash -vx <script> to see how the values are evaluated. This might shed some lights on what goes wrong. — fejese
– fejese, Commented Jul 13, 2015 at 11:34

Community · Accepted Answer · 2017-05-23 12:06:07Z

2

By running bash -vx <script> I found out that the files it was compering was wrong. I needed to change $files[$i] to $i.

$files[$i] = 2015-06-06[2015-06-06]

I have further improved my answer thanks to Etan Reisner comment. By not parsing output from ls.

Reference: https://stackoverflow.com/a/11584156/3371795

#!/bin/bash

# Enable special handling to prevent expansion to a
# literal '/example/backups/*' when no matches are found. 
shopt -s nullglob

        # Variables
        YEAR=`date +%Y`
        MONTH=`date +%m`

        DIR=(/home/user/backups/backup.weekly/*)

        # REGEX - Get curent month
        DATE_RANGE='('$YEAR'\-'$MONTH'\-)[0-9]+\s?'


# Loop through dir
for i in "${DIR[@]}";
do
        # Compare dir name with date range
        if [[ "$i" =~ $DATE_RANGE ]];
        then
                # I have no idea what this is, works fine without it.
                [[ -d "$i" ]] 

                # Echo found dirs
                echo "$i"
        fi
done

edited May 23, 2017 at 12:06

CommunityBot

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answered Jul 13, 2015 at 11:53

Narayana

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5 Comments

Etan Reisner Over a year ago

You shouldn't be parsing the output from ls. Use a glob in that array instead (which may mean needing to strip paths in the loop probably but basename and shell parameter expansion can do that for you).

Narayana Over a year ago

I have updated my answer thanks @EtanReisner. Does anyone know what this is " [[ -d "$i" ]] ", I am unable to find anything on google.

Etan Reisner Over a year ago

[[ is a bash-specific version of [/test with slightly different semantics. -d is "is a directory". Notice in the original it is [[ -d "$folder" ]] && echo "$folder" so that's "if $folder is a directory then echo $folder". On its own [[ -d "$folder" ]] just returns true or false and so in your code it does nothing.

Narayana Over a year ago

Thanks bro, In my scenario I dont see the use for it here ?

Etan Reisner Over a year ago

Written as you have it it has, as I said, no purpose since it just returns true or false and doesn't affect or print anything. In the original with the && it causes the echo to occur only when it returns true (i.e. the folder is a directory).

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