11590Srgrimes# @(#)README 8.1 (Berkeley) 6/6/93 278384Smikeh# 378384Smikeh# $FreeBSD$ 41590Srgrimes 51590Srgrimescol - filter out reverse line feeds. 61590Srgrimes 71590SrgrimesOptions are: 81590Srgrimes -b do not print any backspaces (last character written is printed) 91590Srgrimes -f allow half line feeds in output, by default characters between 101590Srgrimes lines are pushed to the line below 1178384Smikeh -p force unknown control sequences to be passed through unchanged 121590Srgrimes -x do not compress spaces into tabs. 131590Srgrimes -l num keep (at least) num lines in memory, 128 are kept by default 141590Srgrimes 151590SrgrimesIn the 32V source code to col(1) the default behavior was to NOT compress 161590Srgrimesspaces into tabs. There was a -h option which caused it to compress spaces 171590Srgrimesinto tabs. There was no -x flag. 181590Srgrimes 191590SrgrimesThe 32V documentation, however, was consistent with the SVID (actually, V7 201590Srgrimesat the time) and documented a -x flag (as defined above) while making no 211590Srgrimesmention of a -h flag. Just before 4.3BSD went out, CSRG updated the manual 221590Srgrimespage to reflect the way the code worked. Suspecting that this was probably 231590Srgrimesthe wrong way to go, this version adopts the SVID defaults, and no longer 241590Srgrimesdocuments the -h option. 251590Srgrimes 261590SrgrimesKnown differences between AT&T's col and this one (# is delimiter): 271590Srgrimes Input AT&T col this col 281590Srgrimes #\nabc\E7def\n# # def\nabc\r# # def\nabc\n# 291590Srgrimes #a# ## #a\n# 301590Srgrimes - last line always ends with at least one \n (or \E9) 311590Srgrimes #1234567 8\n# #1234567\t8\n# #1234567 8\n# 321590Srgrimes - single space not expanded to tab 331590Srgrimes -f #a\E8b\n# #ab\n# # b\E9\ra\n# 341590Srgrimes - can back up past first line (as far as you want) so you 351590Srgrimes *can* have a super script on the first line 361590Srgrimes #\E9_\ba\E8\nb\n# #\n_\bb\ba\n# #\n_\ba\bb\n# 371590Srgrimes - always print last character written to a position, 381590Srgrimes AT&T col claims to do this but doesn't. 391590Srgrimes 401590SrgrimesIf a character is to be placed on a line that has been flushed, a warning 411590Srgrimesis produced (the AT&T col is silent). The -l flag (not in AT&T col) can 421590Srgrimesbe used to increase the number of lines buffered to avoid the problem. 431590Srgrimes 441590SrgrimesGeneral algorithm: a limited number of lines are buffered in a linked 451590Srgrimeslist. When a printable character is read, it is put in the buffer of 461590Srgrimesthe current line along with the column it's supposed to be in. When 471590Srgrimesa line is flushed, the characters in the line are sorted according to 481590Srgrimescolumn and then printed. 49