Passing a date to a ruby function as STDIN in BASH

Question

I have a ruby file that I would normally run in command line as follows:

ruby file.rb YYYY-MM-DD YYYY_MM_DD

I want to write a bash script to run this file where both YYYY-MM-DD are strings for yesterday's date.

How would I do that?

What does this have to do with STDIN? Command line arguments are not STDIN. — hyde, Mar 02 '14 at 14:54

score 3 · Answer 1 · answered Jul 12 '13 at 20:49

3

ruby file.rb $(date -d yesterday +'%Y-%m-%d') $(date -d yesterday +'%Y_%m_%d')

Note that this will only work in bash. Other Bourne-like shells will work if you use backticks instead of $().

answered Jul 12 '13 at 20:49

Taymon

The caveat is wrong; `$(command)` should work in any POSIX shell. If you're on something truly ancient like SunOS 3, then maybe. – tripleee Jul 13 '13 at 08:20

score 2 · Answer 2 · edited May 23 '17 at 11:49

2

See "YYYY-MM-DD format date in shell script" to figure out how to get the date in whatever format you want.

Yesterday's date can be found as:

date -d '1 day ago' +'%Y/%m/%d'

Replace the / with - or _ and then pass them in to the Ruby statement.

Edit: Vote for the other guy. Their answer actually has code.

edited May 23 '17 at 11:49

Community

answered Jul 12 '13 at 20:50

Paarth

2 Answers2