Que fait la "source" ?

Faites attention ! ./ y source son pas tout à fait la même chose .

• ./script exécute le script comme un fichier exécutable, lançant un nouveau Shell pour l'exécuter
• source script lit et exécute les commandes à partir du nom de fichier dans l'onglet courant Shell environnement

Nota: ./script n'est pas . script mais . script == source script

• Y a-t-il une différence entre "." et "source" dans bash, après tout ?

Il est utile de connaître la commande 'type' :

> type source
source is a shell builtin

chaque fois que quelque chose est un Shell intégré, il est temps de le faire. man bash .

. (une période) est un bash Shell. qui exécute les commandes d'un fichier passé en argument, dans le Shell courant. Source' est un synonyme de '.'.

De la page de manuel de Bash :

. filename [arguments]
source filename [arguments]
       Read  and  execute  commands  from filename in the current shell
       environment and return the exit status of the last command  exe
       cuted from filename.  If filename does not contain a slash, file
       names in PATH are used to find the  directory  containing  file
       name.   The  file  searched  for in PATH need not be executable.
       When bash is  not  in  posix  mode,  the  current  directory  is
       searched  if no file is found in PATH.  If the sourcepath option
       to the shopt builtin command is turned  off,  the  PATH  is  not
       searched.   If any arguments are supplied, they become the posi
       tional parameters when  filename  is  executed.   Otherwise  the
       positional  parameters  are unchanged.  The return status is the
       status of the last command exited within the  script  (0  if  no
       commands  are  executed),  and false if filename is not found or
       cannot be read.

Source" est la version longue de la commande ".". A l'invite de bash, on peut faire :

source ~/.bashrc

pour recharger vos paramètres (modifiés ?) de bash pour le bash en cours d'exécution.

La version courte serait :

. ~/.bashrc

La page de manuel :

. filename [arguments]
source filename [arguments]
    Read and execute commands from filename in the current shell environment and
    return the exit status of the last command executed from filename. If 
    filename does not contain a slash, file names in PATH are used to find the
    directory containing filename. The file searched for in PATH need not be
    executable. When bash is not in posix mode, the current directory is
    searched if no file is found in PATH. If the sourcepath option to the shopt
    builtin command is turned off, the PATH is not searched. If any arguments
    are supplied, they become the positional parameters when filename is
    executed. Otherwise the positional parameters are unchanged. The return 
    status is the status of the last command exited within the script (0 if no
    commands are executed), and false if filename is not found or cannot be
    read.