I saw a post about fix your alias in
And he says after you put your alias in
.bashrc , you need to use:
I do not quite understand what the first dot(' . ') does here. What's its function and what is it called?
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Interesting... the name seems to be
dot-command, in your case it includes the .bashrc into the calling shell program (in your case, your bash environment). As you are calling it from the command line, it updates your environmental variables, as variables are set in .bashrc.
echo "FOO=bar" > test echo $FOO
no result, env variable not set. But after you source the "test" file:
the env variable FOO is set and
result in the output of
I found the following info here:
Sourcing a file (dot-command) imports code into the script, appending to the script (same effect as the #include directive in a C program). The net result is the same as if the "sourced" lines of code were physically present in the body of the script. This is useful in situations when multiple scripts use a common data file or function library.
Also, see this question. In bash,
. is the same as
If you want to check something in bash, use
In your case you want to know what is .
$ type . . is a shell builtin
shell builtin means that . is inside
bash shell. You can find information about shell builtins in
bash manual page. There is a big section SHELL BUILTIN COMMANDS
$ man bash SHELL BUILTIN COMMANDS Unless otherwise noted, each builtin command documented in this section as accepting options preceded by - accepts -- to signify the end of the options. The :, true, false, and test builtins do not accept options and do not treat -- specially. The exit, logout, break, continue, let, and shift builtins accept and process arguments beginning with - with‐ out requiring --. Other builtins that accept arguments but are not specified as accepting options interpret arguments beginning with - as invalid options and require -- to prevent this interpretation. : [arguments] No effect; the command does nothing beyond expanding arguments and performing any specified redirections. A zero exit code is returned. . 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, filenames 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 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.