SYNOPSIStac [options] file [...]
DESCRIPTION
The tac
program prints the given files, but starting from the
end of file, in reverse line order. It is useful for quickly
examining the last few lines of a log file in most-recent order.
Available options are:
-s startexpr
Start printing at the first line that matches the given REX
expression. By default tac
will start printing with the
last line of the file.
-e endexpr
End printing with the first line that matches the given REX
expression. By default tac
will print until the start of
the file is reached. Note: Since tac
reads the file
backwards by default, the startexpr
will occur after
the endexpr
in the original file, even though it appears
first in the output.
-n lines
Read at most this many lines
from the file. This includes
any lines read but not printed before the startexpr
matches. It is a "safety limit" to avoid reading through all of
a very large log file if the start or end expressions are not
found.
-f
Read forward from the start of the file (like cat
) instead
of backwards from the end.
EXAMPLE
Show all of today's web server hits from the log, since midnight.
Note that 13/Apr/1999
is yesterday's date:
tac -e '13/Apr/1999' /usr/local/httpd/logs/transfer.log
SEE ALSO
The Vortex readln
function