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lock 925 B

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  1. .TH LOCK 1
  2. .SH NAME
  3. lock \- run a command under lock
  4. .SH SYNOPSIS
  5. .B lock
  6. [
  7. .B -w
  8. ]
  9. .I lockfile
  10. [
  11. .I command
  12. [
  13. .I argument
  14. \&...
  15. ] ]
  16. .SH DESCRIPTION
  17. .I Lock
  18. runs
  19. .I command
  20. (default
  21. .LR rc )
  22. with
  23. .I arguments
  24. while holding
  25. .I lockfile
  26. open and (over)writing at least one byte each minute
  27. to keep the exclusive-access lock alive.
  28. If
  29. .I lockfile
  30. doesn't already have the exclusive-access bit set in
  31. its mode,
  32. the exclusive-access bits are set in its mode and
  33. .BR qid.type .
  34. .PP
  35. Under
  36. .BR -w ,
  37. .I lock
  38. waits for exclusive access to
  39. .I lockfile
  40. instead of just trying once.
  41. .PP
  42. .I Lock
  43. sets
  44. .B /env/prompt
  45. to contain the name of the lock file.
  46. .SH EXAMPLES
  47. Build a
  48. .IR replica (1)
  49. database while preventing collisions with other occurrences.
  50. .IP
  51. .EX
  52. cd /sys/lib/dist
  53. lock scan.lock replica/scan $dist/sources.replica
  54. .EE
  55. .SH SOURCE
  56. .B /sys/src/cmd/lock.c
  57. .SH SEE ALSO
  58. .IR intro (5),
  59. .IR stat (5)
  60. .\" .SH DIAGNOSTICS
  61. .\" .SH BUGS