1 1.1.1.2 glass # @(#)README 8.1 (Berkeley) 6/6/93 2 1.1 cgd 3 1.1 cgd col - filter out reverse line feeds. 4 1.1 cgd 5 1.1 cgd Options are: 6 1.1 cgd -b do not print any backspaces (last character written is printed) 7 1.1 cgd -f allow half line feeds in output, by default characters between 8 1.1 cgd lines are pushed to the line below 9 1.1 cgd -x do not compress spaces into tabs. 10 1.1 cgd -l num keep (at least) num lines in memory, 128 are kept by default 11 1.1 cgd 12 1.1 cgd In the 32V source code to col(1) the default behavior was to NOT compress 13 1.1 cgd spaces into tabs. There was a -h option which caused it to compress spaces 14 1.1 cgd into tabs. There was no -x flag. 15 1.1 cgd 16 1.1 cgd The 32V documentation, however, was consistent with the SVID (actually, V7 17 1.1 cgd at the time) and documented a -x flag (as defined above) while making no 18 1.1 cgd mention of a -h flag. Just before 4.3BSD went out, CSRG updated the manual 19 1.1 cgd page to reflect the way the code worked. Suspecting that this was probably 20 1.1 cgd the wrong way to go, this version adopts the SVID defaults, and no longer 21 1.1 cgd documents the -h option. 22 1.1 cgd 23 1.1 cgd The S5 -p flag is not supported because it isn't clear what it does (looks 24 1.1 cgd like a kludge introduced for a particular printer). 25 1.1 cgd 26 1.1 cgd Known differences between AT&T's col and this one (# is delimiter): 27 1.1 cgd Input AT&T col this col 28 1.1 cgd #\nabc\E7def\n# # def\nabc\r# # def\nabc\n# 29 1.1 cgd #a# ## #a\n# 30 1.1 cgd - last line always ends with at least one \n (or \E9) 31 1.1 cgd #1234567 8\n# #1234567\t8\n# #1234567 8\n# 32 1.1 cgd - single space not expanded to tab 33 1.1 cgd -f #a\E8b\n# #ab\n# # b\E9\ra\n# 34 1.1 cgd - can back up past first line (as far as you want) so you 35 1.1 cgd *can* have a super script on the first line 36 1.1 cgd #\E9_\ba\E8\nb\n# #\n_\bb\ba\n# #\n_\ba\bb\n# 37 1.1 cgd - always print last character written to a position, 38 1.1 cgd AT&T col claims to do this but doesn't. 39 1.1 cgd 40 1.1 cgd If a character is to be placed on a line that has been flushed, a warning 41 1.1 cgd is produced (the AT&T col is silent). The -l flag (not in AT&T col) can 42 1.1 cgd be used to increase the number of lines buffered to avoid the problem. 43 1.1 cgd 44 1.1 cgd General algorithm: a limited number of lines are buffered in a linked 45 1.1 cgd list. When a printable character is read, it is put in the buffer of 46 1.1 cgd the current line along with the column it's supposed to be in. When 47 1.1 cgd a line is flushed, the characters in the line are sorted according to 48 1.1 cgd column and then printed. 49
Indexes created Mon Sep 29 21:09:56 GMT 2025