Installation manual: Update section "system-wide install"

[mkoeppe]

(split out from #30207)

​https://doc.sagemath.org/html/en/installation/source.html#installation-in-a-multiuser-environment should be updated:

• Don't edit the script
• Just symlink to the sage script in venv

We also add a link from the README to an optional step described only in the installation manual.

[mkoeppe]

New commits:

​60bcbec

README.md, src/doc/en/installation/source.rst: Update multi-user install

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​2116f9f

README.md: Update final step 'symlink sage', add jupyter kernel step

[jhpalmieri]

The suggestion to use

$ sudo ln -s $(sage -sh -c 'ls $SAGE_ROOT/venv/bin/sage') /usr/local/bin

is not consistent with the top-level sage script, which has

if [ -x "$SAGE_ROOT/src/bin/sage" ]; then
    exec "$SAGE_ROOT/src/bin/sage" "$@"
elif [ -x "$SAGE_ROOT/local/bin/sage" ]; then # if in a stripped binary
    # Note in this case we assume that SAGE_LOCAL is the "local" subdirectory
    exec "$SAGE_ROOT/local/bin/sage" "$@"
else
    echo >&2 "$0: no Sage installation found in \$SAGE_ROOT=$SAGE_ROOT"
    exit 1
fi

(a) Should the Sage script look in venv/bin rather than local/bin? (b) Should the suggestion be to make a symlink to SAGE_ROOT/src/bin/sage?

[mkoeppe]

The local/bin/sage could be changed to venv/bin/sage, yes. But this distinction only matters when configure --prefix is not in use because --prefix implies --without-sage-venv. (In Volker's binary build, --prefix is used.)

The "elif" branch is only relevant in binary builds that don't ship src. Do Volker's binary builds (which we no longer advertise) have src?

[mkoeppe]

Do Volker's binary builds (which we no longer advertise) have src?

Actually, this turns out to be irrelevant - it looks like Volker stopped making these binaries altogether, the last one is 9.4 -​http://files.sagemath.org/linux/64bit/index.html

[mkoeppe]

But for the record, ​http://files.sagemath.org/linux/64bit/sage-9.4-Ubuntu_20.04-x86_64.tar.bz2 does have src, but it does not have the symbolic link venv (that was ​introduced in 9.5)

[mkoeppe]

"stripped binary" might refer to what make micro_release creates. I have never used, but I think it is in use in the user-facing Docker containers somehow. It deletes a lot of stuff, but it does leave src/bin around.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​59877bd	Makefile (micro_release): Fix typo in comment
​e537bf3	sage: Remove outdated check for SAGE_ROOT/local/bin/sage

[mkoeppe]

So here's a simplification.

[mkoeppe]

Replying to jhpalmieri:

(b) Should the suggestion be to make a symlink to SAGE_ROOT/src/bin/sage?

No. SAGE_ROOT/sage uses src/bin/sage to allow for uses in unconfigured source trees.

After a build of Sage, using the installed version is more canonical.

[mkoeppe]

Follow-up = #33841

[jhpalmieri]

How can you run

sudo ln -s $(sage -sh -c 'ls $SAGE_ROOT/venv/bin/sage') /usr/local/bin

is sage isn't already in your path?

[mkoeppe]

Thanks for catching this

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​7bc3394

README.md: Use ./sage in command line

[mkoeppe]

(I had copied this from similar invocations shown in src/doc/en/installation/launching.rst, which however start with "Assuming that SageMath can be invoked by typing sage"

[jhpalmieri]

Looks good to me.

[mkoeppe]

Thanks!