Can't get "echo !!" to work in bash from a saved script

Question

I'm trying to write a simple script to take a previous command that was (accidentally) written in a non-English layout, convert everything into correct symbols and run it. I'm using Bash 4.3.11.

My current code looks like this (I'm not a programmer, just trying to learn this for general usability):

echo !! | sed -e "y/first-set-of-symbols/second-set-of-symbols/" | bash

The problem is, when I run the script from a file, I get this: "bash: line 1: !!: command not found", but when I just copy paste the whole command, it does what it's expected to do; if I change the echo part to something like "echo test-command" in the script file, that works when I run the script, too.

Could someone please help me understand why !! isn't working from a script here? Is it supposed to?

I am also open to any suggestions on how to do what I'm trying to do in a better / more efficient / more elegant way.

(I'm not using tr, because, apparently, it doesn't work with Unicode, or so they say—at least it doesn't work for me at all.)

Answer 1

The !! shortcut is only valid for an interactive session. In all other situations it's treated as a literal pair of characters.

Copy'n'paste this to see what's going on:

cat >/tmp/pling.sh <<x
#!/bin/bash
echo hello, world
echo you said !!
x

# Now make the file executable
chmod a+x /tmp/pling.sh

# Now run it
/tmp/pling.sh

Answer 2

Command history isn't enabled in scripts. Even if you enable it, the script has no access to the history of the interactive shell that called it.

Instead of writing a script, make ti a function and put it in your .bashrc.

Also, instead of executing the command in a separate instance of bash, you should probably use the eval builtin to execute it in the same context (same shell variables in particular).

Your approach with history expansion only works for simple commands; commands containing special characters will result in syntax errors or other unintended behavior. Use the fc builtin to access the history programmatically.

reexecute () {
  eval "$(fc -l -1 | sed …)"
}