* How to ensure that /bin takes priority over System32 with "bash -c"? @ 2020-10-31 13:16 Matt D. 2020-10-31 14:21 ` Adam Dinwoodie 0 siblings, 1 reply; 3+ messages in thread From: Matt D. @ 2020-10-31 13:16 UTC (permalink / raw) To: cygwin I have Cygwin's /bin directory configured to be available on my login environment PATH by default. This behavior is inherited when I run a bash login shell: $ where sort C:\cygwin\bin\sort.exe C:\Windows\System32\sort.exe But if I run the following script from a Windows command prompt: C:\> bash -c "where sort" C:\Windows\System32\sort.exe C:\cygwin\bin\sort.exe This creates problems when I want to run a bash script from a process that does not inherit my login environment. Scripts can fail unexpectedly where identically named binaries from System32 take priority. I can't always know what binaries exist in C:\Windows\System32 when writing my scripts. Am I supposed to always launch scripts as "bash --login -i -c"? I don't want or need to have bash run all of its login scripts unnecessarily. How can I run my bash scripts without invoking it as a login shell and ensure that /bin has the environment priority over System32 binaries? ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: How to ensure that /bin takes priority over System32 with "bash -c"? 2020-10-31 13:16 How to ensure that /bin takes priority over System32 with "bash -c"? Matt D. @ 2020-10-31 14:21 ` Adam Dinwoodie 2020-10-31 19:46 ` Brian Inglis 0 siblings, 1 reply; 3+ messages in thread From: Adam Dinwoodie @ 2020-10-31 14:21 UTC (permalink / raw) To: Cygwin (cygwin@cygwin.com) On Sat, 31 Oct 2020 at 13:16, Matt D. via Cygwin wrote: > I can't always know what binaries exist in C:\Windows\System32 when > writing my scripts. Am I supposed to always launch scripts as "bash > --login -i -c"? I don't want or need to have bash run all of its login > scripts unnecessarily. > > How can I run my bash scripts without invoking it as a login shell and > ensure that /bin has the environment priority over System32 binaries? Currently, your commands are doing exactly what you tell them: you're not doing anything to override the PATH from Windows, so they're using the PATH from Windows. On a full Linux system, this is generally not an issue, because you won't have any processes trying to run as children of processes with Windows PATH variables. For most Cygwin users, this isn't a problem because they either (a) just accept the performance impact of running things with a login shell, or (b) (which I suspect is more likely) run most things from within a login shell or some other environment like cron that knows how to set the appropriate variables up. If none of the above are options for you, you'll need to find some way to set the environment variables you need. This might just be starting your Bash commands with `export PATH=/bin:/sbin:$PATH`. Alternatively you could look at using the BASH_ENV environment variable; if you create, say, /etc/bashenv in Cygwin containing `export PATH=/bin:/sbin:$PATH` and any other commands you need, and set BASH_ENV=/etc/bashenv as a Windows system environment variable, I believe Bash should read that when started up in the way you're using it, and assuming you don't have any other non-Cygwin Bash programs on your system (e.g. from Git for Windows), I doubt it'd affect anything else. HTH Adam ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: How to ensure that /bin takes priority over System32 with "bash -c"? 2020-10-31 14:21 ` Adam Dinwoodie @ 2020-10-31 19:46 ` Brian Inglis 0 siblings, 0 replies; 3+ messages in thread From: Brian Inglis @ 2020-10-31 19:46 UTC (permalink / raw) To: cygwin On 2020-10-31 08:21, Adam Dinwoodie wrote: > On Sat, 31 Oct 2020 at 13:16, Matt D. via Cygwin wrote: >> I can't always know what binaries exist in C:\Windows\System32 when >> writing my scripts. Am I supposed to always launch scripts as "bash >> --login -i -c"? I don't want or need to have bash run all of its login >> scripts unnecessarily. >> >> How can I run my bash scripts without invoking it as a login shell and >> ensure that /bin has the environment priority over System32 binaries? > > Currently, your commands are doing exactly what you tell them: you're > not doing anything to override the PATH from Windows, so they're using > the PATH from Windows. > > On a full Linux system, this is generally not an issue, because you > won't have any processes trying to run as children of processes with > Windows PATH variables. For most Cygwin users, this isn't a problem > because they either (a) just accept the performance impact of running > things with a login shell, or (b) (which I suspect is more likely) run > most things from within a login shell or some other environment like > cron that knows how to set the appropriate variables up. > > If none of the above are options for you, you'll need to find some way > to set the environment variables you need. This might just be starting > your Bash commands with `export PATH=/bin:/sbin:$PATH`. Alternatively > you could look at using the BASH_ENV environment variable; if you > create, say, /etc/bashenv in Cygwin containing `export > PATH=/bin:/sbin:$PATH` and any other commands you need, and set > BASH_ENV=/etc/bashenv as a Windows system environment variable, I > believe Bash should read that when started up in the way you're using > it, and assuming you don't have any other non-Cygwin Bash programs on > your system (e.g. from Git for Windows), I doubt it'd affect anything > else. Remember 'where' is like the Windows version of Cygwin which or whereis, so you see only the Windows view of the current PATH: $ where where /t 33280 2019-03-18 22:46:08 C:\Windows\System32\where.exe I export to the env or prefix any such commands, for example, commands that start another mintty window in some arch, WSL distro, etc. or run a script in one of those, with BASH_ENV=$HOME/.bash_env: $ head ~/.bash_env #|/bin/bash # ~/.bash_env - set up bash environment for non-login non-interactive shells export PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:$PATH" -- -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.] ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-10-31 19:46 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-10-31 13:16 How to ensure that /bin takes priority over System32 with "bash -c"? Matt D. 2020-10-31 14:21 ` Adam Dinwoodie 2020-10-31 19:46 ` Brian Inglis
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