On 6/20/20 1:28 PM, Lawrence Velázquez wrote: > Here's something fun though: > > $ PROMPT_COMMAND='cd .' > $ readlink /tmp > private/tmp > $ mkdir /tmp/old > $ cd /tmp/old > $ echo "$PWD" > /tmp/old > $ mv /tmp/old /tmp/new > $ echo "$PWD" > /private/tmp/new > > Not wrong, but maybe unexpected to some.
It's a way to make sure PWD is correct after a `cd'. Without options, `cd' canonicalizes its pathname argument in the way POSIX describes in https://pubs.opengroup.org/onlinepubs/9699919799/utilities/cd.html#tag_20_14 That converts it to /tmp/old ("." -> "/tmp/old/." -> "/tmp/old") Since chdir to "/tmp/old" fails, bash falls back to chdir to ".", which succeeds, and then recanonicalizes PWD to the true directory pathname, as would be returned by `pwd -P'. -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
