CODEWITHSUNDEEP
linuxshell
asif
asif

Reputation: 25

copy and append files in ubuntu linux

I have two folders each containing 351 text files and i want to copy the corresponding text from one folder to corresponding file in another folder? when i am using cat command i am getting an empty file as a result? what could be the problem

my code is :

#!/bin/bash
DIR1=$(ls 2/)
DIR2=$(ls 3/)

for each $i in $DIR1; do
for each $j in $DIR2; do
if [[ $i == $j ]];then
sudo cat $i $j >> $j
fi
done
done

2/ and 3/ are the folders containing the data...

Upvotes: 0

Views: 401

Answers (1)

Bodo
Bodo

Reputation: 9855

DIR1 and DIR2 contain the file names in directories 2 and 3 respectively. Apart from possible problems with spaces or special characters in file names, you would have to use 2/$i and 3/$j. $i and $j alone would reference files with the same names in the current directory (parent of 2 and 3).

It's better not to parse the output of ls. You don't need two nested loops.

#!/bin/bash

DIR1=2
DIR2=3

for source in $DIR1/*
do
    dest="$DIR2/$(basename $source)"

    if [ -f "$dest" ]
    then
        sudo cat "$source" >> "$dest"
    fi
done

see also https://mywiki.wooledge.org/BashPitfalls#for_f_in_.24.28ls_.2A.mp3.29

Depending on your needs it may be better to run the whole script with sudo instead of running sudo for every file. The version above will only execute cat "$source" as root. When running the whole script as root this includes also >> "$dest".

Upvotes: 2

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