Got out with the camera yesterday. Inspired by the fog I saw while walking Gus and Itsy in the wee morning hours. Feels good.
So I installed IPython today. It was a bit of an adventure, so thought I’d document it here, in case it helps anyone else (including my future self, heh):
- Installed Python 3.6 (the default, 2.7, included with macOS, isn’t new enough). This puts the “python3” executable on your machine, which you can invoke similarly to “python” (which will invoke the default OS-supplied Python, probably 2.7).
- Got ‘pip‘. Note this was a convoluted process that involved copying some text from the pip website, pasting it into a text file, then executing that text file from python3 like so: ‘python3 get-pip.py’ (without the quotes). This yielded the ‘pip3.6’ executable, located here: /usr/local/bin/pip3.6
- Used the ‘pip3.6’ executable to download ‘ipython’: /usr/local/bin/pip3.6 install ipython
- Noticed that IPython looked like it installed correctly, but ‘ipython’ didn’t run from the command line immediately after that, and the installation path wasn’t noted anywhere in the installation output. Turns out, IPython added its installation location to my PATH via my .bash_profile file, but didn’t tell me. I reloaded my .bash_profile like this, and all was good: source ~/.bash_profile
- Now I’ve got IPython! Invoke like this from the command line like this: ‘ipython’. Output looks like this:
- Macintodffeb798:local me$ ipython
Python 3.6.3 (v3.6.3:2c5fed86e0, Oct 3 2017, 00:32:08)
Type ‘copyright’, ‘credits’ or ‘license’ for more information
IPython 6.2.1 — An enhanced Interactive Python. Type ‘?’ for help.In :
- Macintodffeb798:local me$ ipython
Simple! Just create an SSH tunnel. Or a couple of them.
Create SSH tunnel to MySQL server running on port 3306 on 192.168.213.207 so that server appears to be running locally on port 3307:
ssh -L 3307:127.0.0.1:3306 firstname.lastname@example.org -NnT
Create SSH tunnel to MySQL server running on port 3306 on machine2 so that server appears to be running locally on port 3308:
ssh -L 3308:127.0.0.1:3306 root@machine2 -NnT
Compare the fancyDatabaseName database on each machine using the
mysqldbcompare tool (part of the
/usr/local/bin/mysqldbcompare --email@example.com:3308 --firstname.lastname@example.org:3307 fancyDatabaseName
Explanation of flags to ‘ssh‘:
Specifies that the given port on the local (client) host is to be forwarded to the given host and port on the remote side. This works by allocating a socket to listen to port on the local side, optionally bound to the specified bind_address. Whenever a connection is made to this port, the connection is forwarded over the secure channel, and a connection is made to host port hostport from the remote machine. Port forwardings can also be specified in the configuration file. IPv6 addresses can be specified with an alternative syntax:
[bind_address/]port/host/hostport or by enclosing the address in square brackets. Only the superuser can forward privileged ports. By default, the local port is bound in accordance with the GatewayPorts setting. However, an explicit bind_address may be used to bind the connection to a specific address. The bind_address of ”localhost” indicates that the listening port be bound for local use only, while an empty address or ‘*’ indicates that the port should be available from all interfaces.
-N will disable the ability to execute a remote command.
-n will prevent reading from stdin.
-T will disable the pseudo-terminal allocation.
This is probably a good argument to just ditch Windows Batch (.bat) files entirely for Windows Powershell scripts, but if you find yourself in a position where this is not feasible, see this Stack Overflow post about how to check the exit codes of programs run within Windows Batch files.
This is still a problem exhibited in Chrome 55 on the Mac (I know, I know, not the very latest available at this moment, but still, pretty new):
“I was prompted (the little up arrow on the wrench icon) to update yesterday (Sept 28 2012), so I did. Now when I open Chrome after shutting it down, it opens my last session. This is not what I want to happen. I have always set Chrome to open my home page on start. I have confirmed my setting is still set to open my home page. I did change the setting to something else and change it back, it didn’t help. Version 22.0.1229.79 m on Windows 7 Ultimate 64 bit”