diff -up src/sage/env.py.orig src/sage/env.py
--- src/sage/env.py.orig	2019-10-03 16:59:18.202495553 -0300
+++ src/sage/env.py	2019-10-03 17:00:31.167931299 -0300
@@ -151,11 +151,11 @@ var('SAGE_DATE',           version.date)
 var('SAGE_VERSION_BANNER', version.banner)
 
 # bunch of sage directories and files
-var('SAGE_LOCAL',          os.path.abspath(sys.prefix))
-var('SAGE_ETC',            join(SAGE_LOCAL, 'etc'))
-var('SAGE_INC',            join(SAGE_LOCAL, 'include'))
-var('SAGE_SHARE',          join(SAGE_LOCAL, 'share'))
-var('SAGE_DOC',            join(SAGE_SHARE, 'doc', 'sage'))
+var('SAGE_LOCAL',          '@@SAGE_LOCAL@@')
+var('SAGE_ETC',            join('/usr', 'share', 'sagemath', 'etc'))
+var('SAGE_INC',            join('/usr', 'include'))
+var('SAGE_SHARE',          join('/usr', 'share', 'sagemath'))
+var('SAGE_DOC',            join('/usr', 'share', 'doc', 'sagemath'))
 var('SAGE_SPKG_INST',      join(SAGE_LOCAL, 'var', 'lib', 'sage', 'installed'))
 var('SAGE_LIB',            os.path.dirname(os.path.dirname(sage.__file__)))
 
@@ -169,7 +169,7 @@ var('DOT_SAGE',            join(os.envir
 var('SAGE_STARTUP_FILE',   join(DOT_SAGE, 'init.sage'))
 
 # installation directories for various packages
-var('SAGE_EXTCODE',                  join(SAGE_SHARE, 'sage', 'ext'))
+var('SAGE_EXTCODE',                  join('/usr', 'share', 'sagemath', 'etc'))
 var('CONWAY_POLYNOMIALS_DATA_DIR',   join(SAGE_SHARE, 'conway_polynomials'))
 var('GRAPHS_DATA_DIR',               join(SAGE_SHARE, 'graphs'))
 var('ELLCURVE_DATA_DIR',             join(SAGE_SHARE, 'ellcurves'))
@@ -181,11 +181,11 @@ var('CREMONA_MINI_DATA_DIR',         joi
 var('CREMONA_LARGE_DATA_DIR',        join(SAGE_SHARE, 'cremona'))
 var('JMOL_DIR',                      join(SAGE_SHARE, 'jmol'))
 var('JSMOL_DIR',                     join(SAGE_SHARE, 'jsmol'))
-var('MATHJAX_DIR',                   join(SAGE_SHARE, 'mathjax'))
+var('MATHJAX_DIR',                   join('/usr', 'share', 'javascript', 'mathjax'))
 var('MTXLIB',                        join(SAGE_SHARE, 'meataxe'))
 var('THREEJS_DIR',                   join(SAGE_SHARE, 'threejs'))
 var('SINGULARPATH',                  join(SAGE_SHARE, 'singular'))
-var('PPLPY_DOCS',                    join(SAGE_SHARE, 'doc', 'pplpy'))
+var('PPLPY_DOCS',                    join('/usr', 'share', 'doc', 'python3-pplpy'))
 var('MAXIMA_FAS')
 
 # misc