Unable to find Perl executable.

After a while that i was not using matlab on my secondary linux pc with manjaro, I don't know why I currently not able to run some commands. I don't know if I messed up with some OS updates or something like that.

In particular if I run

restoredefaultpath;

I've got the following output:

Error using restoredefaultpath (line 36)

Unable to find Perl executable.

I don't know if it could be useful, but if I run

unix('which perl');

I got

/usr/bin/fish: /home/**/Programmi/MATLAB/R2019b/sys/os/glnxa64/libstdc++.so.6: version `GLIBCXX_3.4.29' not found (required by /usr/bin/fish)

/usr/bin/fish: /home/**/Programmi/MATLAB/R2019b/sys/os/glnxa64/libstdc++.so.6: version `CXXABI_1.3.13' not found (required by /usr/bin/fish)

while if I run from terminal 'which perl' command I got '/usr/bin/perl'

Thanks in advance!

Answer 1

[Yongjian Feng]

Acording to this anwer, matlab uses $SHELL to execute shell command. Most likely your SHELL env var is /usr/bin/fish. Check from terminal

echo $SHELL

Change it to /bin/sh or /bin/tcsh

Also your /usr/bin/fish might not be installed properly. If you really want to use /usr/bin/fish, you need to fix it. The following most likely will show the same error as the matlab error you showed.

ldd /usr/bin/fish

[Federico Maggiore]

Thanks for the fast response!

I'm not sure that fish is the problem, I was using it before and I'm currently using it on my laptop without any problem. You're correct saying that the SHELL env var is /usr/bin/fish, but is unclear to me why I sould change it (also there my SHELL env var is /usr/bin/fish but it doesn't give any problem, as it didn't cause any problem some time ago on this PC).

Regarding the

ldd /usr/bin/fish

it gives the following output if I run it in the terminal

linux-vdso.so.1 (0x00007ffc8b1a2000)

libncursesw.so.6 => /usr/lib/libncursesw.so.6 (0x00007f1d5c8e0000)

libdl.so.2 => /usr/lib/libdl.so.2 (0x00007f1d5c8d9000)

libpcre2-32.so.0 => /usr/lib/libpcre2-32.so.0 (0x00007f1d5c855000)

libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f1d5c63f000)

libm.so.6 => /usr/lib/libm.so.6 (0x00007f1d5c4fb000)

libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007f1d5c4da000)

libc.so.6 => /usr/lib/libc.so.6 (0x00007f1d5c30c000)

/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007f1d5cb70000)

libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f1d5c2f1000)

while, as you were predicting, in MATLAB

unix('ldd /usr/bin/fish')

gives the same error as before

[Federico Maggiore]

moreover, following the answer you linked using

setenv SHELL /usr/local/bin/bash

doesn't resolve the problem and

launchctl setenv MATLAB_SHELL /bin/bash

result in "Unrecognized function or variable 'launchctl'."

[Yongjian Feng]

I see.

1. Your system uses /usr/bin/fish for default shell
2. What is the version of the linux you are using now, and what is the matlab version? The root cause here could be that the new upgraded linux version is using some *.so different from your matlab version. For example, the error message suggests that matlab wants to link to the old glib, but the new /usr/bin/fish wants the new glib.
3. If so, you have two options here. Go back to the old linux version that is compatible with your matlab version. Or play with LD_LIBRARY_PATH.

[Federico Maggiore]

I'm using Manjaro 21.2 and matlab 2019b. I don't know what it mens to play with LD_LIBRARY_PATH...