LOCK_FD=200
LOCK_FILE=/tmp/lock-file
exec ${LOCK_FD}>${LOCK_FILE}
I get an error
exec: 200 not found
This however works
LOCK_FD=200
LOCK_FILE=/tmp/lock-file
eval "exec ${LOCK_FD}>${LOCK_FILE}"
Any idea why?
Add a comment
|
1 Answer
Methinks that's because redirection is performed before variable expansion. man bash is not quite clear which is done first:
REDIRECTION Before a command is executed, its input and output may be redirected . . .
EXPANSION Expansion is performed on the command line after it has been split into words.
With the redirection done and removed, exec tries to execute 200 which doesn't exist, and thus the error msg.
