Converting epoch seconds to time inline (preferably vim, but command line would be cool)

Question

I have a file with the format

47 2013-05-01 1367406011 2 30 15
47 2013-05-01 1367406388 1 29 14
43 2013-05-01 1367407469 1 26 12
42 2013-05-01 1367407489 1 25 11
42 2013-05-01 1367407810 1 24 11
39 2013-05-01 1367409056 1 22 9
41 2013-05-01 1367409610 1 22 9
36 2013-05-01 1367411409 1 22 9
34 2013-05-01 1367412388 1 20 9
32 2013-05-01 1367413208 1 19 9

Where the third column is the time the measurement was taken in seconds since epoch. I'd like to be able to see the time as more every day clock time, and I'm looking for the simplest way to have every column in the file converted.

What's the most effective way of performing the conversion? (I'm on OSX)

Answer 1

If you have Perl installed on the machine where you're doing this, and if every line in the file is formatted identically to the example in your question, then the following command line will emit a version of the file with Unix times replaced by human-readable values:

cat source-file | perl -pe's@(^\d+ [\d-]+ )(\d+)@$1 . scalar(localtime($2))@e;'

I'm an Emacs user myself, but I gather from the vim manual that you could apply this command to the contents of your current buffer by doing:

1,$!perl -pe's@(^\d+ [\d-]+ )(\d+)@$1 . scalar(localtime($2))@e;'

Answer 2

In Vim, this quick macro does the job:

qq                           " start recording
0                            " go to first column
2W                           " go to time column
"mciw                        " put time in register m and replace it…
<C-r>=strftime("%T", @m)<CR> " …with localized time
<Esc>                        " exit insert mode
q                            " stop recording

Once the macro is recorded, select all the lines you want to translate then do:

:'<,'>norm @q

If those lines are interleaved with other lines you don't want to touch, you can use the :g[lobal] command to execute the macro only on lines that match some pattern:

:g/2013-05/norm @q

Reference:

:h :normal
:h :global

and

:h strftime()

for date formatting ideas.

With that macro, your sample instantly becomes:

47 2013-05-01 13:00:11 2 30 15
47 2013-05-01 13:06:28 1 29 14
43 2013-05-01 13:24:29 1 26 12
42 2013-05-01 13:24:49 1 25 11
42 2013-05-01 13:30:10 1 24 11
39 2013-05-01 13:50:56 1 22 9
41 2013-05-01 14:00:10 1 22 9
36 2013-05-01 14:30:09 1 22 9
34 2013-05-01 14:46:28 1 20 9
32 2013-05-01 15:00:08 1 19 9