Multiple variable assignments from command output in BASH
day=$(date +%d)
month=$(date +%m)
But, what if we want to perform the same task with just one program invocation? Here comes the power of eval! date(1) outputs a string like "day=29; month=07; year=11" (notice the semicolons I added on purpose at date's custom output) which is a legal shell line. This like is then parsed and executed by the shell once again with the help of eval. Just setting 3 variables!
Inspired by LinuxJournal's column "Dave Taylor's Work the Shell".
$ eval $(date +"day=%d; month=%m; year=%y") $ echo $day/$month/$year 29/07/11
2 Alternatives + Submit Alt
-
This version uses read instead of eval.
58read day month year <<< $(date +'%d %m %y') -
No command substitution but subshell redirection
10read day month year < <(date +'%d %m %y')
What do you think?
Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?
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stat -s some.filest_dev=234881026 st_ino=3657562 st_mode=0100644 st_nlink=1 st_uid=501 st_gid=20 st_rdev=0 st_size=478 st_atime=1312497217 st_mtime=1309535724 st_ctime=1309535724 st_birthtime=1309535658 st_blksize=4096 st_blocks=8 st_flags=0 When you eval the output of stat -s (if you have that option), you get a bunch of variables set.