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ii:labs:01:tasks:02 [2021/10/09 01:10] radu.mantu [02. [40p] tmux] |
ii:labs:01:tasks:02 [2024/10/18 12:14] (current) radu.mantu |
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| **tmux** is a terminal multiplexer. It allows you to split a terminal into multiple views on the same screen, create multiple sessions, etc. | **tmux** is a terminal multiplexer. It allows you to split a terminal into multiple views on the same screen, create multiple sessions, etc. | ||
| - | {{ :ii:labs:01:tasks:tmux-demo.gif?700 |}} | + | [[https://ocw.cs.pub.ro/courses/_media/ii/labs/01/tasks/tmux-demo.gif|{{ :ii:labs:01:tasks:tmux-demo.gif?700 |}}]] |
| + | <html><center><i> Click GIF to maximize. </i></center></html> | ||
| One particularly interesting feature is that you can detach yourself from a session only to reattach later. Take the following scenario: you need to start a process on a remote machine once you **ssh** into it. The process needs to keep running even after you exit. How do you launch that process? | One particularly interesting feature is that you can detach yourself from a session only to reattach later. Take the following scenario: you need to start a process on a remote machine once you **ssh** into it. The process needs to keep running even after you exit. How do you launch that process? | ||
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| $ tmux source-file ~/.tmux.conf | $ tmux source-file ~/.tmux.conf | ||
| </code> | </code> | ||
| + | </note> | ||
| + | |||
| + | <note important> | ||
| + | If you are working in a Virtual Machine, it may be unable to capture key combinations such as //<Ctrl + B>//. There are two alternatives to using these shortcuts. | ||
| + | - right click on the terminal (while running tmux) and drag the mouse. A menu should appear with some basic commands. Drag the cursor over the command and release the mouse button | ||
| + | - run ''tmux split-window''. This command shows all configured binds. We notice the ''split-window [-h]'' command being used, so try running ''tmux split-window'' with a **tmux** instance already running. This will send it a split screen request, just like //<Ctrl + B> "//. | ||
| </note> | </note> | ||
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| === [10p] Task C - Start tmux by default === | === [10p] Task C - Start tmux by default === | ||
| - | If you open a new terminal with //<Ctrl + Alt + T>// you will notice that **tmux** is not running. When **zsh** starts up, it automatically sources //.zshrc//, so lets make it execute **tmux** by adding the following at the end: | + | If you open a new terminal with //<Ctrl + Alt + T>// you will notice that **tmux** is not running. When **zsh** starts up, it automatically sources //.zshrc//, so let's make it execute **tmux** by adding the following at the end: |
| <code> | <code> | ||
| # start tmux session (only once!) | # start tmux session (only once!) | ||
| - | if [ -z "$TMUX" ] && [[ "$USER" == "<YOUR_USERNAME_GOES_HERE>" ]]; then | + | if [ -z "$TMUX" ] && [[ "$USER" == "YOUR_USERNAME_GOES_HERE" ]]; then |
| exec tmux | exec tmux | ||
| fi | fi | ||
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| This may require some explanations. If at any point you're feeling lost, check out the diagram in the spoiler below (or ask). | This may require some explanations. If at any point you're feeling lost, check out the diagram in the spoiler below (or ask). | ||
| * ''[ -z "$TMUX" ]'': Your shell defines some //environment variables// which can be seen by running the ''env'' command. Unless you have an active **tmux** session, there is no //TMUX// variable. So if that variable is empty (which in **bash** / **zsh** means it doesn't exist), we need to start **tmux**. But remember! **tmux** then starts your default shell (i.e.: **zsh**), which sources //.zshrc// again, and executes **tmux**... again... See where I'm going with this? You run into an infinite loop of starting **tmux** and **zsh** and your terminal will simply crash. So we need to start **tmux** __exactly__ once. | * ''[ -z "$TMUX" ]'': Your shell defines some //environment variables// which can be seen by running the ''env'' command. Unless you have an active **tmux** session, there is no //TMUX// variable. So if that variable is empty (which in **bash** / **zsh** means it doesn't exist), we need to start **tmux**. But remember! **tmux** then starts your default shell (i.e.: **zsh**), which sources //.zshrc// again, and executes **tmux**... again... See where I'm going with this? You run into an infinite loop of starting **tmux** and **zsh** and your terminal will simply crash. So we need to start **tmux** __exactly__ once. | ||
| - | * ''%%[[%% "$USER" == "..." %%]]%%'': This is a solution for a rather dumb problem. Up until now, you've set up **zsh** only for your user but not for //root//. If you create// /root/.zshrc// and in it you just source the main //.zshrc// in your home, you will end up executing **tmux** again, but only once more. The reason is that the //TMUX// environment variable is not passed to the new user's shell. Why this is annoying is that the second **tmux** instance will add another status bar to the bottom of your screen. Normally, when you start a terminal with //<Ctrl + Alt + T>// you don't run a shell a root, so this workaround is somewhat valid. | + | * ''%%[[%% "$USER" == "..." %%]]%%'': This is a solution for a rather dumb problem. Up until now, you've set up **zsh** only for your user but not for //root//. If you create// /root/.zshrc// and in it you just source the main //.zshrc// in your home, you will end up executing **tmux** again, but only once more. The reason is that the //TMUX// environment variable is not passed to the new user's shell. Why this is annoying is that the second **tmux** instance will add another status bar to the bottom of your screen. Normally, when you start a terminal with //<Ctrl + Alt + T>// you don't run a shell as //root//, so this workaround is somewhat valid. |
| * ''exec tmux'': By running ''tmux'' you will be able to ''exit'' or //<Ctrl + D>// and you'll return to the original **zsh** shell. By running ''exec tmux'' you will effectively //replace// your current shell, so when you exit, you will close the entire terminal window. | * ''exec tmux'': By running ''tmux'' you will be able to ''exit'' or //<Ctrl + D>// and you'll return to the original **zsh** shell. By running ''exec tmux'' you will effectively //replace// your current shell, so when you exit, you will close the entire terminal window. | ||
| <spoiler> | <spoiler> | ||
| - | {{ :ii:labs:01:tasks:tmux-zsh-flow.png?400 |}} | + | [[https://ocw.cs.pub.ro/courses/_media/ii/labs/01/tasks/tmux-zsh-flow.png|{{ :ii:labs:01:tasks:tmux-zsh-flow.png?500 |}}]] |
| </spoiler> | </spoiler> | ||
