How to Use Z Shell (zsh) on a Cloud Server
This articles covers how to use zsh on an cloud server. You can verify that zsh is installed on your VPS by simply trying to start it:
If you have zsh installed, you will launch right into that shell.
Otherwise, it is recommended that you install zsh before proceeding.
It might be difficult at this point to understand how much more powerful zsh is than a shell like bash. Let’s start by looking into the autocomplete capabilities of the shell.
Let’s imagine that we want to install “vim-addon-manager” to help us organize our text editor configuration file. We can’t remember what the package is called though. Instead of using apt-cache to search for the package name, we can just use zsh to give a list of packages that start with “vim”.
sudo apt-get install vim<tab>
vim vim-doc vim-lesstif vim-scripts vim-addon-manager vim-gnome vim-migemo vim-syntax-go vim-athena vim-gtk vim-nox vim-syntax-gtk vim-common vim-gui-common vim-puppet vim-tiny vim-conque vimhelp-de vim-rails vim-vimoutliner vim-dbg vim-latexsuite vim-runtime
When we use <tab> completion with apt, we see that it gives us a list of available packages. We can then type in the additional letters needed to get a unique hit. In this case, typing “-ad<tab>” will complete the command as needed.
sudo apt-get install vim-ad<tab>
Let’s make our autocomplete even more powerful. Let’s add the following section to our .zshrc:
zstyle ‘:completion:*’ menu select setopt completealiases
This will do two things. It will let us autocomplete any aliases that we might write in our .zshrc, and it also lets us select out of a menu when there are multiple selections available. Let’s source the .zshrc file again to load our changes and then try the apt-get example again.
source ~/.zshrc sudo apt-get install vim<tab>
It looks the same. The difference is that now we can press the <tab> key again and then use the <tab> and arrow keys to select your options. This can result in selecting much faster in some cases.
One of the options we set up initially was to use extended globbing expressions. Globbing is a type of syntax that uses special symbols to match and filter results when searching or passing arguments to any program or function.
Let’s try a few examples. First, we’ll try some more traditional globbing in case you aren’t familiar with the idea. Let’s create a testing directory and populate it with some files.
mkdir test cd test touch file1 file2 file3 file100 file120 file122 file200 file222 touch file250 file800 file808 file80 somefile anotherfile touch thisotherfile file.txt file.c file.o file.html file.css touch completelydifferent different separate mkdir directa directb directc directd
Our test directory now has a good number of files and directories that we can select and manipulate.
Let’s select everything with the word file in it. The asterisk (*) character stands in for 0 or more characters.
anotherfile file120 file200 file3 file808 file.html somefile file1 file122 file80 file.c file.o thisotherfile file100 file2 file250 file800 file.css file.txt
The result is every file with the word “file” in its title. Let’s say that we only want to find files that begin with “file”.
file1 file122 file222 file80 file.c file.o file100 file2 file250 file800 file.css file.txt file120 file200 file3 file808 file.html
This cuts down on our results a bit, but let’s narrow this down further. The caret character (^) is used to negate the pattern following. So let’s say we want all files that start with “file” but we don’t want any where “1” is immediately following “file”.
file2 file222 file3 file800 file.c file.html file.txt file200 file250 file80 file808 file.css file.o
Let’s say we want to find all files that begin with “file” and have a number afterwards ranging from 100 to 300. We can use the less than (<) and greater than (>) signs to enclose a range of numbers.
file100 file120 file122 file200 file222 file250
If we want all of those results, but we specifically do not want file200, we can tell zsh to not select it with the tilde (~) character.
file100 file120 file122 file222 file250
Let’s do some more complex selections. We can qualify our results further by providing a selector within a set of parentheses. If we want to select everything that is a regular file (not a directory, a link, etc), we can use something like this.
anotherfile file100 file200 file80 file.css separate completelydifferent file120 file222 file800 file.html somefile different file122 file250 file808 file.o thisotherfile file1 file2 file3 file.c file.txt
Notice how none of the directories that we created are listed. If instead, we only want directories, we can use this:
directa: directb: directc: directd:
Next, let’s select the 5 newest files in our test directory. We can do that by using the “o” qualifier in parentheses. This selects our sorting method. We’re going to follow the “o” with an “m” which means we’re sorting by modification time. Finally, we’ll provide a range in brackets that tells zsh how many results we want.
completelydifferent different file.css file.html separate
Here are some extra ideas to try out.
We can configure zsh to automatically use specific programs to open a file based on the file extension. We will accomplish this using “suffix aliases”. These can be added to our .zshrc so that if we simply type the name of a file and hit return, it will be opened with the correct program.
Let’s use “less” to open any files with an extension of .view and use “nano” to open any files that end in .edit. Add this line to the bottom of your .zshrc.
alias -s view=less alias -s edit=nano
Now, let’s create two files to test this on.
touch test.view test.edit
If we type:
The file will open in “less” when we hit enter. However, if we type:
The file will open in nano, as expected.
Another nice thing that zsh provides for us is completion hinting. The zsh gives us great visual indicators when it comes to entering multi-lined input. Let’s give it a try. If we type something like this and hit “enter”:
print “this is a line
We’ll be presented with a prompt like this:
We can complete this line by ending our input with the second set of double quotes.
dquote> that goes onto the next line”
As you can see, it tells us what kind of input needs to be closed to complete the statement. We can see a similar thing happen if we try to type a simple shell script into the prompt.
if [[ -o interactive ]]; then then> print yes then> else else> print no else> fi
As you can see, it gives us the same kind of hinting. This can be very helpful if you have long input statements that span multiple lines.
Setting zsh as the default shell
If you decide that zsh on a cloud server is suitable for your daily shell needs, you can make it the default shell for your user. This way, every time you log in, your preferences will be loaded and a zsh session will be spawned. You will no longer have to type “zsh” to get to zsh in your VPS.
chsh -s $(which zsh)
Next time you log in, you’ll be presented with a zsh prompt.
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