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I'm generating models in Ruby on Rails, and some of these tables have an awful lot of columns. What's maximum length of a command in Mac OS X?

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The limit is not in bash but in your operating system. It's defined by the value of ARG_MAX in your OS's limits.h. You can get the value by running getconf ARG_MAX. On my OSX 10.5 machine (and most other BSD systems) it's 262144. You can read more about this limit here.

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    On Solaris 10, it is 1048320 - both are so big that they boggle the mind that someone might run out of it. – Jonathan Leffler Sep 29 '09 at 2:53
  • Excellent. I guess I was a was away yet. lol – DGM Sep 29 '09 at 3:17
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    As of macOS 10.12, the limit is still 262,144 (256 KB). Note that the limit only applies when invoking external utilities, not shell builtins. Compare echo "$(printf "%$(getconf ARG_MAX)s")" to /bin/echo "$(printf "%$(getconf ARG_MAX)s")" – mklement Jan 17 '17 at 17:54
  • High Sierra (10.13.1) here, still 262144. – Siu Ching Pong -Asuka Kenji- Nov 29 '17 at 10:28
  • @JonathanLeffler Searching through a few thousand files will quickly make that number very small. – Clearer Apr 17 '18 at 13:37
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It depends on the shell, but the last time I ran a configure script using zsh on 10.6 it was 65535 characters.

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