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Frequently asked questions

Why does cd, $PWD and and various fish commands always resolve symlinked directories to their canonical path?

For example if ~/images is a symlink to ~/Documents/Images, if I write 'cd images', my prompt will say ~/D/Images, not ~/images.

Because it is impossible to consistently keep symlinked directories unresolved. It is indeed possible to do this partially, and many other shells do so. But it was felt there are enough serious corner cases that this is a bad idea. Most such issues have to do with how '..' is handled, and are varitations of the following example:

Writing cd images; ls .. given the above directory structure would list the contents of ~/Documents, not of ~, even though using cd .. changes the current directory to ~, and the prompt, the pwd builtin and many other directory information sources suggest that the current directory is ~/images and its parent is ~. This issue is not possible to fix without either making every single command into a builtin, breaking Unix semantics or implementing kludges in every single command.

This issue can also be seen when doing IO redirection.

Another related issue is that many programs that operate on recursive directory trees, like the find command, silently ignore symlinked directories. For example, find $PWD -name '*.txt' silently fails in shells that don't resolve symlinked paths.

I accidentally entered a directory path and fish changed directory. What happened?

If fish is unable to locate a command with a given name, and it starts with '.', '/' or '~', fish will test if a directory of that name exists. If it does, it is implicitly assumed that you want to change working directory. For example, the fastest way to switch to your home directory is to simply press ~ and enter.

The open command doesn't work.

The open command uses the MIME type database and the .desktop files used by Gnome and KDE to identify filetypes and default actions. If at least one of these environments is installed, but the open command is not working, this probably means that the relevant files are installed in a non-standard location. Consider asking for more help.

How do I make fish my default shell?

If you installed fish manually (e.g. by compiling it, not by using a package manager), you first need to add fish to the list of shells by executing the following command (assuming you installed fish in /usr/local) as root:

echo /usr/local/bin/fish >>/etc/shells

If you installed a prepackaged version of fish, the package manager should have already done this for you.

In order to change your default shell, type:

chsh -s /usr/local/bin/fish

You may need to adjust the above path to e.g. /usr/bin/fish. Use the command which fish if you are unsure of where fish is installed.

Unfortunately, there is no way to make the changes take effect at once. You will need to log out and back in again.

I'm seeing weird output before each prompt when using screen. What's wrong?

Quick answer:

Run the following command in fish:

echo 'function fish_title;end' > ~/.config/fish/

Problem solved!

The long answer:

Fish is trying to set the titlebar message of your terminal. While screen itself supports this feature, your terminal does not. Unfortunately, when the underlying terminal doesn't support setting the titlebar, screen simply passes through the escape codes and text to the underlying terminal instead of ignoring them. It is impossible detect and resolve this problem from inside fish since fish has no way of knowing what the underlying terminal type is. For now, the only way to fix this is to unset the titlebar message, as suggested above.

Note that fish has a default titlebar message, which will be used if the fish_title function is undefined. So simply unsetting the fish_title function will not work.

How do I change the greeting message?

Change the value of the variable fish_greeting. For example, to remove the greeting use:

set fish_greeting

Why doesn't history substitution ("!$" etc.) work?

Because history substitution is an awkward interface that was invented before interactive line editing was even possible. Fish drops it in favor of perfecting the interactive history recall interface. Switching requires a small change of habits: if you want to modify an old line/word, first recall it, then edit. E.g. don't type "sudo !!" - first press Up, then Home, then type "sudo ".

Fish history recall is very simple yet effective:

See documentation for more details about line editing in fish.

Uninstalling fish

Should you wish to uninstall fish, first ensure fish is not set as your shell. Run chsh -s /bin/bash if you are not sure.

Next, do the following (assuming fish was installed to /usr/local):

rm -Rf /usr/local/etc/fish /usr/local/share/fish ~/.config/fish
rm /usr/local/share/man/man1/fish*.1
cd /usr/local/bin
rm -f fish mimedb fish_pager fishd fish_indent

Generated on Thu May 16 09:27:20 2013 for fish by  doxygen 1.5.9