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by yjftsjthsd-h 330 days ago
Why

  (; flock -n 9
and not

  ( flock -n 9

?
1 comments
apopapo 330 days ago
It's a "for" loop.
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marklgr 330 days ago
Could you elaborate?
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apopapo 330 days ago
A for loop in a shell script may sometimes look like this:

`for ((i = 0 ; i < max ; i++ )); do echo "$i"; done`

Here this is essentially a "while" loop, meaning it will keep executing the commands as long as we don't reach `exit 1`.

(; flock -n 9 || exit 1; # ... commands executed under lock ...; )

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yjftsjthsd-h 328 days ago
It doesn't seem to work?

  [~] 0 $ ( flock -n 9 || exit 1; echo in loop ; sleep 3 ; echo done working ; ) 9>~/tmp/mylock
  in loop
  done working
  [~] 0 $ (; flock -n 9 || exit 1; echo in loop ; sleep 3 ; echo done working ; ) 9>~/tmp/mylock
  -bash: syntax error near unexpected token `;'
  [~] 2 $
(This is bash)
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