Question

Given files named 1.csv, 2.csv, 3.csv, …89.csv… n.csv
how do I append them together in numeric order)(1 to n) in bash shell script?
is there a one-liner for the solution?

Answer 1

If your files where named with leading zeros, it would be easier, i.e.

  cat [0-9].csv [0-9][0-9].csv .... > new.csv

But its not too hard to get a true numeric order, given

ls -1
1
10
11
12
13
2
20
21
3
7
8
9

(in both samples, note that the option to ls is the number one, (1), not the letter L (l))

AND

ls -1 [0-9]* | sort -n
1
2
3
7
8
9
10
11
12
13
20
21

THEN

  cat $( ls -1 *.csv | sort -n  ) > new.csv

Assuming all your csv files are numbered.

If you have more than 1000 files, file arg processing in the shell may break down, and you should post a new question for correct use of xargs.

To see what is happening add shell debugging/trace use

 set -vx  # to turn on
 set +vx  # to turn it off

.

IHTH.