On Fri, 2002-11-22 at 14:56, Todd Lyons wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > ath1410 wrote on Fri, Nov 22, 2002 at 05:04:55PM +0900 : > > > > I checked the sites you refered, but did not still quite figure > > out (partly because of my poor English?) the way bash works the > > way it does. To make things simple, just take up one case here. > > $PS1=\\\\u -4 returns \u > > the 1st \ escapes the 2nd \, and the 3rd one to the 4th one > > likewise. > > So $PS1=\\\\u is something like $PS1='\\u' ( which actually > > returns \u, not user name. > > Yes. > > The following are identical: > PS=\\\\u > PS="\\\\u" > > > This is NOT the same: > PS='\\\\u' > > Nor seemingly is this because of the single quoting which prevents > parameter expansion. I honestly thought it _would_ be the same, but if > you say it doesn't work, then it doesn't work: > PS='\\u' > > The trick is that bash parses each commandline twice (repeating someone > else's authoritative post from memory, so anybody more knowledgable, > please feel free to correct errors). The first time it converts "\\" to > "\" and "\\" to "\", leaving you with "\\u". The second time it > converts "\\" to "\", leaving you with "\u". That is what then gets > used.
Actually no, it is parsed 3 times: once when you enter it not quoted in the command line, a second time by the prompting decoding (only certain specific backslah substitutions performed) and a third time if you variable promptvars is set (set by default, see shopt). This explain the small number of \ in the display prompt compared to what you used in the command line. Guillaume. > Blue skies... Todd > - -- > MandrakeSoft USA http://www.mandrakesoft.com > cat /boot/vmlinuz > /dev/dsp #for great justice > Cooker Version mandrake-release-9.1-0.1mdk Kernel 2.4.20-0.2mdk > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.2.1 (GNU/Linux) > > iD8DBQE93ovilp7v05cW2woRAvyzAJ4sSqW6ez0W0GgYdIWGFMKs30zU1QCgrQxl > ilYHcg/BLdcHjVTiGikMhaE= > =LR3p > -----END PGP SIGNATURE----- > > ---- > > Want to buy your Pack or Services from MandrakeSoft? > Go to http://www.mandrakestore.com
Want to buy your Pack or Services from MandrakeSoft? Go to http://www.mandrakestore.com
