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Month: September 2020

change default postscript viewer (and other apps too) in nautilus file manager

Published by jweisber on 2020-09-25

to change default postscript viewer (or many other apps in nautilus) go to

/home/jweisber/.local/share/applications and
open mimeapps.list with kate or another text editor.

Go to default applications category (in mine it is the bottommost of 3 categories) and change the postscript viewer to

application/postscript=kde4-okularApplication_fb.desktop. if you’d like to change it to okular

I find okular great for a number of reasons – it will print the name of displayed file on the banner, show thumbnails of multiple pages, and more.  Evince is another nice one.  The default was gv which is ok but . . .

(I stole that from the top list which gave about 5 options, presumably the ones that appear in the nautilus menu when you go to file>>open with

–Joel

idl unix-like commands – see also 2023 11 03

Published by jweisber on 2020-09-02

OK.  idl has some built-in unix-like commands, but then others require a ‘$’ beforehand  which I think summons the unix shell.  The various unix-like commands that an idl user might like are a mixture thereof, so see below whether or not there is a $  (See also a third option, spawn, below.):

cd, ‘/data/psrdata/   note no $ : this is a native idl command made to look like its unix cousin

pwd                         ”       ”   ”     ”        ”  (This and previous command often go together ,
since this one returns the “present working directory” which should
verify that your cd command did as you wished! (There is supposedly a
way to get the idl prompt to show the pwd but I haven’t yet figured it out.)

printd or popd or pushd are all native idl directory-oriented commands made to look like their unix cousins (or in printd case, just print the current directory name – no unix cousin exists.)

$ls     Needs the dollar sign which I think invoked the unix shell.

The idl spawn command can also be useful: 

spawn,’ls -als | grep arecibowapp’ is a way to do the idl version of the unix  ls with flags, and even then pipe it into another command. This looks like the most flexible!.

spawn,’ps aux’  ditto