The mistery of <<<
 

Hello!
I try to execute command:
# cut -d . -f 2 < tmp.pyMANw61Ev
bash: tmp.pyMANw61Ev: No such file or directory

But when I type
# cut -d . -f 2 <<< tmp.pyMANw61Ev
pyMANw61Ev

It works great! What is the special symbol <<<?

well you're asking it to do a different thing, one doesn't "not work".

< will redirect from a *FILE* called tmp.pyMANw61Ev but here you seem to be wanting to split a string, so the two things are not comparable.

< - Redirection
<< - Here document
<<< - Here string