I have 2 questions about using PIP requirements.txt with a constraint.
Let's say I have a requirements.txt file and I add a constraint file. What happens if I try to specify a different version in req.txt than that which is in the constraints? For example in my req file it says x==1.2 but in my constraint file it says x==1.1
Will it install either version of x? Or neither version?
When using a constraint file which specifies let's say x==1.1, is it best to remove the version number from x in the req.txt?
I tried testing this out, but wasn't sure if either version was getting installed. I expect that it will install the version in the constraints and not the version in the req.txt
Related
I realize that a requirements.txt file can be used to pin the versions used in pip install. Sometimes I don't want to go through all that- and just simply want to protect my installation from downgrades. Is there any way to instruct pip install to do that?
An example: I just installed librosa and it downgraded numpy from 1.24.1 to 1.23.5 . I don't want that behavior to happen unless I explicitly request. On the other hand if there are missing dependencies then please let's grab them.
For this installation of python it is acceptable to take the risk of occasionally ending up with a mismatch due to installing newer versions [ but I don't want older ones].
During apt upgrade I got an output like the following, unfortunately I pressed enter by mistake. Which is why a package was kept in the previous version. I think it was openssh-server, but I am not sure. I am using Raspberry Pi OS in the current version on a Raspberry Pi 4.
Configuration file '/etc/foo/foo.conf'
==> Modified (by you or by a script) since installation.
Version in package is the same as at last installation.
What would you like to do about it ? Your options are:
Y or I : install the package maintainer's version
N or O : keep your currently-installed version
D : show the differences between the versions
Z : start a shell to examine the situation
The default action is to keep your current version.
*** foo.conf (Y/I/N/O/D/Z) [default=N] ?
My question is how can I re-trigger the update, or check which package was affected and reinstall that? I already ran apt upgrade again, but it said that 0 new packages can be loaded or installed.
I'd like to distribute multiple versions of a package through conda. Specifically, I'd like to do something like this:
...
package-v1.2-dev
package-v1.2
package-v1.1-dev
package-v1.1
package-v1.0
The trick is that I'd like to have the "latest" or default package be the release versions that do not have -dev. As I understand it, conda install <package> without a version number will install the newest build. In my case, that will always be -dev. Is it possible to make the default a specific version number?
You can achieve this by specifying a custom "label" for your dev packages. Keep using the default main label for your release packages, but use a non-main label (e.g. dev) for the other packages.
First, a quick note about version numbers: conda package versions must not contain the - character, so v1.2-dev is not a valid version. For the following examples, I'll use v1.2.dev.
Here's how to upload your packages:
anaconda upload mypackage-v1.2.tar.bz2
anaconda upload --label dev mypackage-v1.2.dev.tar.bz2
(You can also manipulate the labels for existing packages via your account on the http://anaconda.org website.)
By default, your users will only download your main packages. Users who want the dev packages will have two choices:
They can specify the dev label on the command-line:
conda install -c mychannel/label/dev mypackage
OR
They can add your dev label to their .condarc config
# .condarc
channels:
- mychannel/label/dev # dev label
- mychannel # main label only
- conda-forge
- defaults
And then there's no need to specify the channel on the command-line:
conda install mypackage
PS -- Here's a side note about something you wrote above:
As I understand it, conda install <package> without a version number will install the newest build
Just to clarify, it doesn't install the "newest" in chronological sense, but rather the highest compatible version according to conda's VersionOrder logic. That logic is designed to be largely compatible with relevant Python conventions (e.g. PEP440 and others), but with some affordances for compatibility with other languages' conventions, too.
Please note: As far as conda (and PEP440) is concerned, 1.2.dev comes BEFORE 1.2. (Maybe you already knew that, but I don't consider it obvious.)
$ python
>>> from conda.models.version import VersionOrder
>>> VersionOrder('1.2.dev') < VersionOrder('1.2')
True
The rpm command provides three main operations for upgrading and installing packages:
Upgrade
An upgrade operation means installing a new version of a package and removing all previous versions of the same package. If you have not installed a package previously, the upgrade operation will install the package.
Freshen
A freshen operation means to install a new version of a package only if you have already installed another version of the package.
Install
An install operation installs a package for the first time. It also, through special command-line parameters, allows you to install multiple versions of a package, usually not what we want. So, in the vast majority of cases, you want to run the upgrade operation for all package installations.
Should normally install packages with rpm -U, not rpm -i. One of the main reasons is that rpm -i allows you to install multiple instances of the same (identical) package.
Is this the standard conclusion or
should I stop installing the second instance of the package along with the first instance by writing any wrapper script or by adding code in spec file section.
If 2 point is the answer how can achieve this. Please guide me about this confusion.
Assuming you only every want one version of an RPM installed at once, then yes use "rpm -U".
Creating an RPM that can have multiple versions installed requires that all common files between the versions are identical. This frequently happens, so you may get this behaviour "by default".
You can also prevent multiple versions with the following in you spec:
Conflicts : %{name} < %{version}
Today I installed the curl formula via homebrew, but after installing it (and re-sourcing the shell) i noticed that :
% which curl
/usr/bin/curl
as a matter of fact, the output of brew install curl stated that it was a keg-only formula, and that since curl was already present in OS X, it didn't link it into Homebrew prefix, as that could cause unspecified problems.
Then it proceeds stating that
Generally there are no consequences of this for you
I would like to know:
What sorts of problems exactly?
What is the purpose of installing keg-only formulas via Homebrew? How can there be no consequences if the newly installed tool is not in the PATH?
Problems: if a homebrew application is put in the path in front of the default OS X version of the same, really anything might happen. Most common issues are caused by differences between the set of command line options available in the two versions, or differences in the meaning of the options. For curl the consequences might not be so bad, but for other applications you could, at worst, break the OS.
Keg-only: now you have two versions of curl! The default OS X, and the homebrew. If you want to use features that are not in the default but in the homebrew, you can do so by calling the homebrew curl explicitly. The precise path depends on how you've got homebrew set up. Because the newly installed version is not in the path, its unlikely to cause a problem unless it is explicitly called.
I want to add some complement to the second problem(related to the mechanism of keg-only) asked by #asymmetric.
HomeBrew's prefix is /usr/local , and HomeBrew keeps all installed kegs in the default directory, say /usr/local/Cellar. In general, HomeBrew could create symlink for installed formula(non-keg-only formula), and the corresponding symlink is kept in /usr/local/bin. This symlink-creation procedure is automatic when HomeBrew installing the formula. Here the path /usr/local/bin would be called default (symlink) prefix.
On the other hand, according to FAQ of HomeBrew, we have the following guidance:
``keg-only formula is installed only into the Cellar and is not linked into the default prefix. This means most tools will not find it.''
But at the same time the HomeBrew creates symlinks in the directory /usr/local/opt for ALL installed formulae no matter whether they are keg-only or not.
There will be two crucial points we should notice:
By default the default (symlink) prefix /usr/local/bin is in PATH, but the non-prefix /usr/local/opt is NOT in PATH.
By default the default (symlink) prefix /usr/local/bin in general points towards the latest version of formula. So if you want to use the specific version(often in keg-only format) of some formula you could temporarily prepend your PATH with the keg-only formula's bin directory, for example, export PATH="$(brew --prefix)/opt/FormulaName/bin:${PATH}".
The setting of /usr/local/opt mentioned above could resolve the executable-conflict. In general, you might have a formula or program in your system with many different versions, such as the latest version and outdated version, the Apple native version and locally installed version, an so on. It's possible for these situations to cause conflict when you execute or compile some other programs which are somewhat related to the current using formula or program.