Extraños errores "command not found" y "No such file or directory".

Errores muy extraños de múltiples formas:

1. Ejecutar brew install c-ares falla con command not found , aparentemente ni siquiera ejecutando brew :

   $ brew install c-ares
   -bash: brew install c-ares: command not found

   Sin embargo, brew install cmake ejecuta brew como se esperaba:

   $ brew install cmake
   Warning: Treating cmake as a formula. For the cask, use homebrew/cask/cmake
   Warning: cmake 3.25.1 is already installed and up-to-date.
   To reinstall 3.25.1, run:
     brew reinstall cmake

2. No se puede anteponer /usr/local/opt/qt5/bin a $PATH con el error No such file or directory :

   $ export PATH=/usr/local/opt/qt5/bin:$PATH
   -bash: export PATH=/usr/local/opt/qt5/bin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/usr/local/MacGPG2/bin:/opt/X11/bin:/Library/Apple/usr/bin: No such file or directory

   Esa carpeta existe:

   $ [ -d /usr/local/opt/qt5/bin ] && echo "exists"
   exists

   Como todos los demás en $PATH :

   $ echo $PATH
   /usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/usr/local/MacGPG2/bin:/opt/X11/bin:/Library/Apple/usr/bin
   $ for i in $(echo $PATH | awk -F: '{for (i=1; i<=NF; i++) { print $i; }}'); do if [ -d "$i" ]; then echo "$i exists"; else echo "$i does not exist"; fi; done
   /usr/local/bin exists
   /System/Cryptexes/App/usr/bin exists
   /usr/bin exists
   /bin exists
   /usr/sbin exists
   /sbin exists
   /Library/TeX/texbin exists
   /usr/local/MacGPG2/bin exists
   /opt/X11/bin exists
   /Library/Apple/usr/bin exists

   Sin embargo, añadir /tmp funciona:

   $ export PATH=/tmp/:$PATH
   $ echo $PATH
   /tmp/:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/usr/local/MacGPG2/bin:/opt/X11/bin:/Library/Apple/usr/bin

3. Los mismos errores con zsh :

   $ zsh
   % brew install c-ares
   zsh: command not found: brew install c-ares
   % brew install cmake
   Warning: Treating cmake as a formula. For the cask, use homebrew/cask/cmake
   Warning: cmake 3.25.1 is already installed and up-to-date.
   To reinstall 3.25.1, run:
     brew reinstall cmake
   % export PATH=/usr/local/opt/qt5/bin:$PATH
   zsh: no such file or directory: export PATH=/usr/local/opt/qt5/bin:/tmp/:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/usr/local/MacGPG2/bin:/opt/X11/bin:/Library/Apple/usr/bin

Estoy bastante desconcertado y no sé cómo depurar los shell built-ins.

No se me ocurre nada que haya cambiado recientemente que pueda causar esto. Hoy he actualizado a Ventura 13.1 con la esperanza de que desapareciera, pero ya ocurría antes de la actualización y sigue ocurriendo.

He probado a reiniciar y no ha servido de nada.

Información del sistema:

% system_profiler SPSoftwareDataType SPHardwareDataType | grep -v -e UUID -e UDID -e 'User Name' -e 'Computer Name' -e Serial
Software:

    System Software Overview:

      System Version: macOS 13.1 (22C65)
      Kernel Version: Darwin 22.2.0
      Boot Volume: MainDisk
      Boot Mode: Normal
      Secure Virtual Memory: Enabled
      System Integrity Protection: Disabled
      Time since boot: 22 minutes, 2 seconds

Hardware:

    Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: MacBookPro15,1
      Processor Name: 6-Core Intel Core i7
      Processor Speed: 2.6 GHz
      Number of Processors: 1
      Total Number of Cores: 6
      L2 Cache (per Core): 256 KB
      L3 Cache: 9 MB
      Hyper-Threading Technology: Enabled
      Memory: 16 GB
      System Firmware Version: 1916.60.2.0.0 (iBridge: 20.16.2059.0.0,0)
      OS Loader Version: 564.40.4~55
      Activation Lock Status: Enabled