How can I convert a file full of unix time strings to human readable dates?

Question

I am processing a file full of unix time strings. I want to convert them all to human readable.

The file looks like so:

1153335401
1153448586
1153476729
1153494310
1153603662
1153640211

Here is the script:

#! /bin/bash
FILE="test.txt"
cat $FILE | while read line; do
perl -e 'print scalar(gmtime($line)), "\n"'
done

This is not working. The output I get is Thu Jan 1 00:00:00 1970 for every line. I think the line breaks are being picked up and that is why it is not working. Any ideas? I'm using Mac OSX is that makes any difference.

Answer 1

$ perl -lne 'print scalar gmtime $_' test.txt
Wed Jul 19 18:56:41 2006
Fri Jul 21 02:23:06 2006
Fri Jul 21 10:12:09 2006
Fri Jul 21 15:05:10 2006
Sat Jul 22 21:27:42 2006
Sun Jul 23 07:36:51 2006

Answer 2

Because $line is in single quotes, it's not being processed by bash, and so $line is treated as an (undefined) Perl variable rather than a bash variable.

You don't need a while read bash loop; Perl can do the looping itself using its -n option.

perl -nE 'say scalar(gmtime($_))' test.txt

(using -E to enable say, which automatically appends a newline)