CODEWITHSUNDEEP
bash
GuitarExtended
GuitarExtended

Reputation: 827

Concatenate text files in a specific order with Bash

Say I have a directory containing 5 files :

file1.md
another file.md
and yet another one.md
some other file.md
And the last one.md

Files may have spaces in their name.

Now suppose I have a file containing an ordered list of the filenames above :

And the last one.md
another file.md
and yet another one.md
file1.md
some other file.md

What Bash script could I use in order to concatenate all six files into a new one, following the order defined in the ordered list ? I'm using Bash on Windows. The context is that I want to be able to reorder small parts of a larger text, such as short stories or chapters in a book.

Upvotes: 1

Views: 645

Answers (2)

David Lukas
David Lukas

Reputation: 1229

You can use while read.

rm output.txt;cat input.txt | while read row; do cat "$row" >> output.txt; done

Alternatively:

while read row; do cat "$row"; done < input.txt > output.txt

The command reads rows from the input.txt and appends the contents of the files to the output.txt. Double quotes are good for spaces in file names.

My attempt:

Creating data (optional):

 while read row; do echo "$row" "mm" > "$row"; done

Shift + Ins
Ctrl + c

$ cat file1.md
file1.md mm
$ ls -1
'And the last one.md'
'and yet another one.md'
'another file.md'
file1.md
input.txt
output.txt
'some other file.md'

Output:

$ cat output.txt
And the last one.md mm
another file.md mm
and yet another one.md mm
file1.md mm
some other file.md mm

Change order of names:

$ cat input.txt
another file.md
and yet another one.md
some other file.md
And the last one.md
file1.md

$ rm output.txt;cat input.txt | while read row; do cat "$row" >> output.txt; done

$ cat output.txt
another file.md mm
and yet another one.md mm
some other file.md mm
And the last one.md mm
file1.md mm

Upvotes: 0

KamilCuk
KamilCuk

Reputation: 140960

The following should be just enough:

xargs -d '\n' cat < file_containing_an_ordered_list_of_the_filenames.txt

Upvotes: 3

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