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bashsvngrephead

Prevent "head" from waiting for the stream to end

svn log -r HEAD:1 | grep $pattern --line-buffered | awk '{print $1}'

The above prints out revision numbers for all commits the match the pattern (e.g. are done by a certain user). This works fine except it keeps streaming the entire svn log (which might be very long) and will only end after it reaches its end.

Since I only need the most recent history I've tried this:

svn log -r HEAD:1 | grep $pattern --line-buffered | awk '{print $1}' | head

However this just hangs - I'm assuming it's waiting for the stream to end but that's unacceptable to me.

How do I prevent head from waiting for the stream to end (and instead finish immediately after getting 10 lines)?

Solution

  • Since I only need the most recent history

    I think you required -m option with grep.

    Try this:

    svn log -r HEAD:1 | grep -m 1 "$pattern"
    • -m NUM - Stop reading a file after NUM matching lines.