Show HN: Justpath – a simple utility to explore the PATH environment variable (opens in new tab)

(github.com)

76 pointsepogrebnyak2y ago26 comments

26 comments

For zsh I use this to setup $PATH, which seems to address most of the use cases of this tool:

  ### Setup PATH
  dirs=(
      /usr/lib/ccache/bin                   # ccache
      ~/.local/script ~/.local/bin          # My local scripts.
      ~/.local/gobin                        # GOBIN
      /usr/local/bin /usr/local/sbin        # local takes precedence
      /bin /sbin /usr/bin /usr/sbin         # Standard Unix
      /usr/pkg/bin   /usr/pkg/sbin          # NetBSD
      /usr/X11R6/bin /usr/X11R6/sbin        # OpenBSD
      /opt/ooce/bin                         # illumos
      ~/.local/share/gem/ruby/*/bin(N[-1])  # Ruby
      ~/.luarocks/bin(N[-1])                # Lua
      ~/.local/dotnet/root ~/.local/dotnet/tools  # .NET
      /usr/lib/plan9/bin                    # Plan 9 from userspace
      ~/code/Vim/gopher.vim/tools/bin       # gopher.vim
      ~/.nimble/bin                         # Nim
      ~/.cargo/bin                          # Rust
      ~/.ghcup/bin                          # Haskell
  )
  typeset -U path=()                        # No duplicates
  # Use full path so /bin and /usr/bin aren't duplicated if it's a symlink.
  for d in $dirs:A; [[ -d $d ]] && path+=($d)
  unset dirs d

typeset -U makes the $path array "unique", and :A ensures the full path is always used (in case of symlinks).

You can probably do something similar with bash, but idk.

$path is tied to $PATH and an array, so you can use it as such for some of the other things:

  print ${(F)path} | grep /bin  # (F) to print one array per line
  print ${(F)path} | sort       # can also use (o) to print ordered

throwaway848462y ago

I use 'path=( ${(u)^path:A}(N-/) )' instead of that for loop

mst2y ago

To just reduce the current entries to those that exist, I'd probably do

    PATH=$(perl -e 'print join ":", grep -d, split ":", $ENV{PATH}')

but that's because as a 20 year perl hacker and thus connoiseur of line noise, I'd rather read that than the shell clever.

(this doesn't mean the shell clever is bad, it just means I don't find -that- dialect of line noise as skimmable)

1 more reply

adriangrigore2y ago

Plan 9 from User Space binaries are on /usr/local/plan9/bin/ on OpenBSD.

epogrebnyakOP2y ago

How does (N[-1]) get resolved?

arp2422y ago

(N) sets the NULL_GLOB option for that pattern:

    % print doesnt-exist*
    zsh: no matches found: doesnt-exist*
    % print doesnt-exist*(N)
    (doesn't print anything, pattern is just ignored)

([n]) is array indexing to get entry n; -1 gets the last entry:

    % print a*
    a-1 a-2 a-3
    % print a*([-1])
    a-3
    % print a*([1])
    a-1

Globbing is automatically sorted by name.

So putting that together, things like this:

      ~/.local/share/gem/ruby/*/bin(N[-1])  # Ruby

will use the latest Ruby version in ~/.local/share/gem/ruby, and it won't error out if it doesn't exist (so I can freely copy this around even to machines without Ruby, or remove Ruby, etc).

1 more reply

DanielKehoe2y ago

I'd like to hear viewpoints on using `~/.zprofile` versus `~/.zshrc` for setting `$PATH` on macOS. I was bothered for years that I didn't know the difference so I dived down the rabbit hole and wrote a guide [1]. In the end, I concluded:

- Use `~/.zprofile` to set the PATH and EDITOR environment variables. - Use `~/.zshrc` for aliases and a custom prompt, or anything tweaking the appearance and behavior of the terminal.

It seems the advantage of the `~/.zprofile` file versus `~/.zshenv` is that it sets environment variables such as `$PATH` without override from macOS. It seems the `~/.zshrc` file could be used for `$PATH` but, by convention and design, is intended for customizing the look and feel of the interactive terminal.

Frankly, saying `~/.zprofile` is better than `~/.zshrc` for setting `$PATH` only "by convention and design" feels like a cop-out. Wondering if anyone knows better.

[1] https://mac.install.guide/terminal/zshrc-zprofile

sidneythekidney2y ago

I set $PATH in ~/.zshenv. If you don't, you can't use any of your "extra stuff" in your zsh-scripts, as they do not use login or interactive sessions. And then I unset GLOBAL_RCS so the system configfiles don't override my settings.

In your guide, under ~/.zshenv, you mention that "macOS overrides this for PATH settings for interactive shells", without mentioning why or how. What's happening is that macOS sets your path in /etc/zprofile.

It seems your guide is missing a few global configfiles :) This is the order for an interactive login shell [1]:

  /etc/zshenv
  ${ZDOTDIR:-$HOME}/.zshenv
  /etc/zprofile                 (login)
  ${ZDOTDIR:-$HOME}/.zprofile   (login)
  /etc/zshrc                    (interactive)
  ${ZDOTDIR:-$HOME}/.zshrc      (interactive)
  /etc/zlogin                   (login)
  ${ZDOTDIR:-$HOME}/.zlogin     (login)
  /etc/zlogout                  (login - loaded on logout)
  ${ZDOTDIR:-$HOME}/.zlogout    (login - loaded on logout)

In fact, the configfiles you mention are only loaded the way you've mentioned them, if the option GLOBAL_RCS is unset. And if GLOBAL_RCS is unset, macOS does not override your PATH, because/etc/zprofile is not loaded :)

1: <https://zsh.sourceforge.io/Doc/Release/Files.html>

DanielKehoe2y ago

Thank you! That's informative.

1 more reply

vim-guru2y ago

Your assessment is correct. But it really comes down to what type of shell that's running. For an interactive shell (one you open yourself in a terminal), the run-com file (.zshrc) will be loaded, so anywhere you put it, things will seemingly work. But if you start doing some task scheduling etc, that would fail if you have set your PATH in a run-com.

vim-guru2y ago

I think for most of its use-cases, you could replace it with a one-liner: alias path='echo -e ${PATH//:/\\n} ' and work with it via sort and uniq. I've had this alias in my configuration for a couple of decades now, so I'm not bashing on its usefulness though.

nmz2y ago

or you could just check env for a special variable and load a file once if the env var exists.

nolongerthere2y ago

I’m struggling to understand the use case for this aside from just checking if your own directory is on the path.

OccamsMirror2y ago

Not bad for a security check.

https://systemweakness.com/linux-privilege-escalation-using-...

epogrebnyakOP2y ago

For me the use case was trying to understand what directories should I clean from path and if there where duplicates. Just something to help understand if my PATH on Windows was repetitive or not.

epogrebnyakOP2y ago

Actually funny enough does not do that - cool possible feature

Should it be `justpath --contains .`?

Opened issue here: https://github.com/epogrebnyak/justpath/issues/10

nolongerthere2y ago

I was thinking you’d pipe the results and check that way

agumonkey2y ago

the original ~unionfs :)

nmz2y ago

Kinda pointless

rrosen3262y ago

I like it! I do the steps involved in this occasionally, manually. It’s not hard but this makes it nice. Not sure I’ll use it since it is one more thing to install and remember, but the author had an itch and scratched it. Well done.

epogrebnyakOP2y ago

Thanks! Indeed an itch that was both on Linux and Windows - so a tool that I could use in either environment

dang2y ago

Url changed from https://polar.sh/epogrebnyak/posts/justpath-to-explore-path-..., which points to this.

j / k navigate · click thread line to collapse

26 comments

arp2422y ago

For zsh I use this to setup $PATH, which seems to address most of the use cases of this tool:

  ### Setup PATH
  dirs=(
      /usr/lib/ccache/bin                   # ccache
      ~/.local/script ~/.local/bin          # My local scripts.
      ~/.local/gobin                        # GOBIN
      /usr/local/bin /usr/local/sbin        # local takes precedence
      /bin /sbin /usr/bin /usr/sbin         # Standard Unix
      /usr/pkg/bin   /usr/pkg/sbin          # NetBSD
      /usr/X11R6/bin /usr/X11R6/sbin        # OpenBSD
      /opt/ooce/bin                         # illumos
      ~/.local/share/gem/ruby/*/bin(N[-1])  # Ruby
      ~/.luarocks/bin(N[-1])                # Lua
      ~/.local/dotnet/root ~/.local/dotnet/tools  # .NET
      /usr/lib/plan9/bin                    # Plan 9 from userspace
      ~/code/Vim/gopher.vim/tools/bin       # gopher.vim
      ~/.nimble/bin                         # Nim
      ~/.cargo/bin                          # Rust
      ~/.ghcup/bin                          # Haskell
  )
  typeset -U path=()                        # No duplicates
  # Use full path so /bin and /usr/bin aren't duplicated if it's a symlink.
  for d in $dirs:A; [[ -d $d ]] && path+=($d)
  unset dirs d

typeset -U makes the $path array "unique", and :A ensures the full path is always used (in case of symlinks).

You can probably do something similar with bash, but idk.

$path is tied to $PATH and an array, so you can use it as such for some of the other things:

  print ${(F)path} | grep /bin  # (F) to print one array per line
  print ${(F)path} | sort       # can also use (o) to print ordered

throwaway848462y ago

I use 'path=( ${(u)^path:A}(N-/) )' instead of that for loop

mst2y ago

To just reduce the current entries to those that exist, I'd probably do

    PATH=$(perl -e 'print join ":", grep -d, split ":", $ENV{PATH}')

but that's because as a 20 year perl hacker and thus connoiseur of line noise, I'd rather read that than the shell clever.

(this doesn't mean the shell clever is bad, it just means I don't find -that- dialect of line noise as skimmable)

1 more reply

adriangrigore2y ago

Plan 9 from User Space binaries are on /usr/local/plan9/bin/ on OpenBSD.

epogrebnyakOP2y ago

How does (N[-1]) get resolved?

arp2422y ago

(N) sets the NULL_GLOB option for that pattern:

    % print doesnt-exist*
    zsh: no matches found: doesnt-exist*
    % print doesnt-exist*(N)
    (doesn't print anything, pattern is just ignored)

([n]) is array indexing to get entry n; -1 gets the last entry:

    % print a*
    a-1 a-2 a-3
    % print a*([-1])
    a-3
    % print a*([1])
    a-1

Globbing is automatically sorted by name.

So putting that together, things like this:

      ~/.local/share/gem/ruby/*/bin(N[-1])  # Ruby

will use the latest Ruby version in ~/.local/share/gem/ruby, and it won't error out if it doesn't exist (so I can freely copy this around even to machines without Ruby, or remove Ruby, etc).

1 more reply

DanielKehoe2y ago

- Use `~/.zprofile` to set the PATH and EDITOR environment variables. - Use `~/.zshrc` for aliases and a custom prompt, or anything tweaking the appearance and behavior of the terminal.

Frankly, saying `~/.zprofile` is better than `~/.zshrc` for setting `$PATH` only "by convention and design" feels like a cop-out. Wondering if anyone knows better.

[1] https://mac.install.guide/terminal/zshrc-zprofile

sidneythekidney2y ago

It seems your guide is missing a few global configfiles :) This is the order for an interactive login shell [1]:

  /etc/zshenv
  ${ZDOTDIR:-$HOME}/.zshenv
  /etc/zprofile                 (login)
  ${ZDOTDIR:-$HOME}/.zprofile   (login)
  /etc/zshrc                    (interactive)
  ${ZDOTDIR:-$HOME}/.zshrc      (interactive)
  /etc/zlogin                   (login)
  ${ZDOTDIR:-$HOME}/.zlogin     (login)
  /etc/zlogout                  (login - loaded on logout)
  ${ZDOTDIR:-$HOME}/.zlogout    (login - loaded on logout)

1: <https://zsh.sourceforge.io/Doc/Release/Files.html>

DanielKehoe2y ago

Thank you! That's informative.

1 more reply

vim-guru2y ago

nmz2y ago

or you could just check env for a special variable and load a file once if the env var exists.

nolongerthere2y ago

I’m struggling to understand the use case for this aside from just checking if your own directory is on the path.

OccamsMirror2y ago

Not bad for a security check.

https://systemweakness.com/linux-privilege-escalation-using-...

epogrebnyakOP2y ago

For me the use case was trying to understand what directories should I clean from path and if there where duplicates. Just something to help understand if my PATH on Windows was repetitive or not.

epogrebnyakOP2y ago

Actually funny enough does not do that - cool possible feature

Should it be `justpath --contains .`?

Opened issue here: https://github.com/epogrebnyak/justpath/issues/10

nolongerthere2y ago

I was thinking you’d pipe the results and check that way

agumonkey2y ago

the original ~unionfs :)

nmz2y ago

Kinda pointless

rrosen3262y ago

epogrebnyakOP2y ago

Thanks! Indeed an itch that was both on Linux and Windows - so a tool that I could use in either environment

dang2y ago

Url changed from https://polar.sh/epogrebnyak/posts/justpath-to-explore-path-..., which points to this.

j / k navigate · click thread line to collapse