mkcd() { mkdir -vp "$1" && cd "$1"; }

mkcd() { mkdir -p "$@" && cd "$_"; }

Can someone please detail the differences between $! and $_? (Apologies if I'm missing something obvious)

  $ echo "test" > /dev/null && echo !$
  /dev/null
  $ echo "test" > /dev/null && echo $_
  test

I would not that !$ is a bash-ism, whereas $_ works at least on zsh and ksh as well as bash.

     alias tcd='a=`date +%s`;mkdir "$a" && cd "$a"'

Further, holding Alt followed by numeric argument followed by dot, gives you an argument at a specific position. For example, Alt + 1, Alt + . copies the first argument.

!-1:gs/hello/world

which runs the last command with all instances of hello replaced by world. !-1 can be any so called event designator, for instance !n to refer to any specific line number from history or !string for last command containing a particular string.

Seriously people, read the man page for bash. Your shell has so many cool features.

$ echo "hello hello hello world" hello hello hello world $ ^hello^bonjour^ echo "bonjour hello hello world" bonjour hello hello world

Why? The last command is more general, you can just drop the g from the command I wrote to only replace the first occurrence. Besides, :[g]s/old/new should already be familiar to anyone who has used vim, so that is almost like having to learn zero new things.

^-t

No, more having to press C-r multiple times just to get sequential group of commands from history.

Also keep in mind that most interactive command-line tools are built upon readline and can understand all those bindings (think python REPL, mysql/psql...)

Haha of course. I use it so frequently I can't imagine how anyone uses their shell without it.

>can understand all those bindings

I knew that but just being reminded helped me realize that C-o is probably going to be useful in the REPL as well. Thanks.

Real programmers use set -o vi

Bash is more than just bash. Composition is a killer technique.

    # create a new directory and enter it
    function mkd() {
        mkdir -p "$@" && cd "$_";
    }

What does: "mkd foo bar" do? It creates both directories, and cd's into "bar".

Might be worth checking that only one argument has been passed, or use "$*" which instead would treat all arguments as one parameter, and "mkd foo bar" would create a "foo bar" directory instead (and cd to it)

YMMV.

It's also a good way to "learn by doing", which works for many.

¹ https://github.com/ohmyzsh/ohmyzsh/blob/master/lib/functions...

Wrote about it here: https://henrikwarne.com/2018/08/11/my-favorite-command-line-...

"Insert last argument to the previous command (the last word of the previous history entry). With a numeric argument, behave exactly like yank-nth-arg. Successive calls to yank-last-arg move back through the history list, inserting the last word (or the word specified by the argument to the first call) of each line in turn."

https://tiswww.case.edu/php/chet/readline/readline.html#IDX9...

Its sibling is `yank-nth-arg`, bound to M-C-y. So if you want the 2nd argument from the last command, you can press M-1 followed by M-C-y (yeah, arguments are indexed from 0)...

https://tiswww.case.edu/php/chet/readline/readline.html#IDX9...

That's great set of tips BTW.

FWIW, zsh without oh-my-zsh can be configured to do too this with "bindkey ' ' magic-space".

    enter () 
    { 
        mkdir -p "$1";
        cd "$1"
    }

And !$ is documented here: https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash....

!! -> last whole command

!!:1 -> first argument of last command

!!:$ -> last argument of last command

!$ -> abbreviation for above