berch%lll-tis.arpa@lll-tis.ARPA@sri-unix.UUCP (08/30/84)
From: "Michael C. Berch" <berch%lll-tis.arpa@lll-tis.ARPA> > From: kemp@noscvax.UUCP (Stephen P. Kemp): > tail -r filename > lists the file backwards. > > From: ihnp4!zehntel!zinfandel!berry > Well, on my VAX 750 with 4.1BSD, tail -r of a LARGE file prints the > last block or two backwards, then gives up. I have noticed the same result: % wc gnu 932 7461 45463 gnu % tail -r gnu | wc 98 651 4096 The answer is that the manual entry for tail(1) is incorrect. The entry says that with the -r flag, the ENTIRE FILE will be displayed in reverse order. But the header comment in the code and the code itself state that ONE INPUT BUFFER'S WORTH of the file will be put out (backwards, from the end) with the -r flag. On our systems (2.9BSD and 4.2BSD) the buffer size (LBIN in tail.c) is 4097 characters. Thus `tail -r' will not put out more than 4097 characters. There is undoubtedly some way (using the -NN/+NN flags) to get -r to do the whole file but someone else will have to find it. Michael Berch Control Data Corp. / Lawrence Livermore Natl. Laboratory berch@lll-tis ...ucbvax!lbl-csam!lll-tis!berch