“Event not found” error for shell command in unix [duplicate]

问题

This question already has answers here:

echo “#!” fails — “event not found” (5 answers)

Closed last year.

when i am trying to remove consecutive duplicate lines with

awk "!x[$0]++" file

its reporting x[: Event not found.

even the same case with

sed -i -e "$!N; /^\(.*\)\n\1$/!P;D" file as well reporting

N: Event not found. i tried with single quotes too, it didn't help

Any idea to fix those

回答1:

You're invoking the shell's history substitution. Surround the exclamation point with single quotes.

来源：https://stackoverflow.com/questions/10221835/event-not-found-error-for-shell-command-in-unix