On 18/01/17 16:39, f0rhum wrote: > Hi > This is about tail v5.97 > I have a log file that is updated every 5mn, a timestamped message being > appended to a new line at the end > On the third time an indentical message would be writen, the last line > is replaced by "..." then the message is writen > > Tracking changes with tail -f stops after this, which may be intended > behaviour as man states "as the file grows". > > Although, when pruning a bunch of lines from the head of the file, then a > yet running tracking still won't update even the file size grows, like if the > file size was > grabbed on the very beginning of the command and never updated on each > iteration. > > To be honest, I didn't try to see what happens if I prune a single line > and see what the next 2nd and further iterations show.
I think you're saying that your file is truncated in place. tail(1) doesn't handle that well and expects files to be increasing, and maybe rotated (which is handled with -F). Newer versions of tail(1) will show the whole file again once it detects truncation (as usually a truncated file is truncated to nothing before new data is written). cheers, Padraig
