Shellscripting question

How could I make a shellscript which will echo "Welcome home, oniichan!" whenever I cd to my home directory?

perhaps I could make a shellscript like this:
#!/bin/bash
cd ~
echo "Welcome home, oniichan!"
and then just alias it to "home"

but can you even alias shellscripts?

>>2
You may alias anything.

>>2

you should call it hm for EXPERT UNIX READABILITY

>>2
although you'd need to be careful, since this would change the directory in the shell script, not the parent shell, so when the script exited, you'd be back at where you were in the parent shell. It's tricky.

>>5
2/10. Go back to /g.

wat

alias cd ~ = 'cd ~ && echo "what"'

>>8
alias cd ~ = 'cd ~ && echo "what"'
Am I just dumb, or isn't it a bad idea to alias something to itself? Wouldn't the output of that aliased command be ``cd ~ what cd ~ what cd ~ what cd ~ what cd ~ what''... etc

Reminds me of something similar:
(save as what.bat)
@echo off
:start
echo what
what.bat
goto start

also I am high as fuck

smoke weed everyday, it makes thinking more difficult

If using zsh:
function cd () {
        if ! test "$@"; then
                $HOME || return $?
        else
                $@ || return $?
        fi
        if test "$PWD" = "$HOME"; then
                echo 'Welcome home, oniichan!'
        fi
}

>>9
That should be start what.bat to create a new process/window. Without start, the batch file never resumes and goto start is never reached. A common bug in batch files is to forget start or call, so the original batch file never resumes. The default behavior without call is to pop the entire chain of batch files from the call stack. Why did Microsoft decide that you need call for batch files instead of having them behave like any other executable? Because changing the default behavior would break compatibility with QDOS. Even in the early 1980s Microsoft and Intel products were full of kludges for backwards compatibility.

>>10
What part of this does not work with bash?

>>12
$HOME || return $? and $@ || return $?.
In zsh, you can change directory like you'd run an executable, the cd isn't needed.

>>13
You should've used chdir $HOME instead (also doesn't work in bash), otherwise you could do stupid stuff like cd /bin/ls.

>>13
bash version:
cd () {
    if ! test "$@"; then
        pushd $HOME > /dev/null || return $?
    else
        pushd $@ > /dev/null || return $?
    fi 
    if test "$PWD" = "$HOME"; then
        echo 'Welcome home!'
    fi 
}

>>1
You can start with something like
export PS1='$(if [ $PWD == $HOME ]; then echo "Welcome home, oniichan! "; fi)\$ '
It works in bash and changes your prompt every time you are in your home directory.

As for echoing a welcome message only when $PWD changes to your $HOME, I don't know, for one thing there's a shitload of things that can change your $PWD, also it would be all kinds of annoying if it fucked up scripts accidentally.

~/bin/cd:
#!/bin/sh
cd "$@"
if [ $PWD = $HOME ]
then
    echo "Welcome home, weeaboo!"
fi

.bashrc, .zshrc, etc.:
alias cd=~/bin/cd

>>17
You're only changing the directory in the new sh process.

>>18
alias cd='exec ~/bin/cd'

Wait, I actually have an idea.

You can use persistent state in your PS1 "script". Apparently, it's impossible to store it in environment variables, but you can always store it in a temp file. So you can see if $PWD has changed between two invocations of PS1. And you can output \n or two after the welcome message, to make it appear separate from the prompt.

>>19
That'll just close your shell.
Better also put exec $SHELL on the bottom of your ~/bin/cd.

Note that is horribly inefficient, makes your shell restart every time and parse its configuration files (and print any fortunes or whatever) every time you cd. >>13 is a way better solution.

>>21
Meant >>15, not >>13.

>>17 that would suck because 1) there are other ways to change current directory, like pushd/popd, 2) you don't want scripts that might change a directory to pollute their stdout with bullshit (I guess you can check if stdout is a tty).

But on the other hand, as I understand a buggy incomplete solution that does one thing only sometimes and does it badly is exactly what UNIX Way is about, so in this respect your approach is fine.

OK, I kind of did it.

Put this in your .bashrc:

export WELCOMEPWD=`mktemp -t`
export PS1='$(~/bin/welcome.sh)'$PS1

Put this in ~/bin/welcome.sh:

#!/bin/sh
if [ -n "$WELCOMEPWD" -a -f "$WELCOMEPWD" ] ; then
    if [ "$PWD" != "`cat "$WELCOMEPWD"`" ] ; then
        if [ "$PWD" = "$HOME" ]; then
            echo -e "Welcome home, oniichan!\n\n "
        fi
        echo "$PWD" > "$WELCOMEPWD"
    fi
fi

The problem is that fucking space, because otherwise fucking bash strips trailing newlines from anything that executes inside $() or ``, and this can't be disabled. So you have to put the beginning of your prompt in the script/command.

echo "fuck you japan faggot"