Bash variable expansion in command

Question

DATE="1 week ago"
date --date='$DATE'

doesn't work. How can I get it to work?

I could do:

DATE_CMD="date --date='$DATE'"
eval $DATE_CMD

but I don't want to store the entire command in a variable.

score 2 · Answer 1 · answered Sep 24 '13 at 07:00

2

You just need to use double-quotes to enable string interpolation:

date --date="$date"

answered Sep 24 '13 at 07:00

nneonneo

1

Another quick response. Yes, this works too. Thought I'd direct readers to this topic which explains it quite nicely: http://stackoverflow.com/questions/6697753/difference-between-single-and-double-quotes-in-bash – Ash Sep 24 '13 at 07:07

score 2 · Accepted Answer · answered Sep 24 '13 at 07:00

2

You're a victim of quote expansion.

The proper invocation would likely be:

DATE='1 week ago'
date --date="$DATE"

(notice the double quotes)

answered Sep 24 '13 at 07:00

JB.

1

Wow! That was the quickest solution I've ever received! Can't even accept your answer yet since I have to wait 11 minutes (apparently). – Ash Sep 24 '13 at 07:02

2 Answers2