unifile

• vastblue.file.Paths.get() returns a java.nio.file.Path object
• extensions to java.nio.Paths for cygwin, msys2, git-bash and other Windows posix-shell environments.
• Expressive, Platform-portable scala library.
• Simplify system administration tasks.
• no 3rd party libraries, 100% scala.

For unifile functionality, reading of .csv, Date & Time functions, and more, see Pallet (has 3rd party dependencies).

Write portable code that runs on Linux, Mac, or Windows. Converting path Strings to java.nio.file.Path objects.

Recognizes posix file paths in Windows, via customizable mount points in C:/msys64/etc/fstab.

• Supported Scala Versions

  • scala 3.x

• Tested Target environments

  • Linux
  • Darwin/OSX
  • Windows
    • Cygwin64
    • Msys64
    • Mingw64
    • Git-bash
    • WSL Linux

Usage

To use unifile in an SBT project, add this dependency to build.sbt

  "org.vastblue" % "unifile_3" % "0.4.1"
For `scala 3.5+` or `scala-cli` scripts:
  "//> using dep org.vastblue:unifile_3:0.4.1"

## TL;DR
Simplicity and Universal Portability:
* Script as though you're running in a Linux environment.
* extend the range of your programs to include `cygwin` and other Windows shell environments.
* read process command lines from `/proc/$PID/cmdline` files
## Requirements
In Windows, requires a posix shell:
  * [MSYS64](https://msys2.org)
  * [CYGWIN64](https://www.cygwin.com)
  * [Git Bash](https://www.atlassian.com/git/tutorials/git-bash)
  * [WSL](https://learn.microsoft.com/en-us/windows/wsl/install)

Example scripts require a recent version of coreutils:
  (e.g., `ubuntu`: 8.32-4.1ubuntu1, `osx`: stable 9.4)
to support the use of `-S` in `#!/usr/bin/env -S scala-cli shebang` in hash-bang lines.

### Concept
  * import vastblue.unifile.*
* Provides `vastblue.file.Paths` for converting path strings to `java.nio.file.Paths`
  * `Paths.get` returns `java.nio.file.Path` objects
  * `Paths.get("/etc/fstab").toString` == `/etc/fstab` in most environments
  * `Paths.get("/etc/fstab").toString` == `C:\msys64\etc\fstab` (in MSYS64, for example)
  * `Paths.get("/etc/fstab").posx`     == `C:/msys64/etc/fstab`

Examples below illustrate some of the capabilities.

### Background
Most platforms other than `Windows` are unix-like, but with differing conventions and
various incompatibilities:
   * Linux / OSX `/usr/bin/env`, etc.

Windows shell environments are provided by `cygwin64`, `msys64`, `Git-bash`, etc.
However, the `Windows` jvm doesn't recognize the filesystem abstractions of these environments.

This library provides the missing piece.

  * In Windows, a custom `Paths.get()` applies `/etc/fstab` mounts before returning a `java.nio.file.Path`
  * In other environments, it uses plain vanilla `java.nio.file.Paths.get()`
  * extension methods on `java.nio.file.Path` and `java.io.File` simplify writing portable code

### Example script: display the native path and the number of lines in `/etc/fstab`
The following example might surprise Windows developers, since JVM languages don't normally support posix file paths that aren't also legal Windows paths.

```scala
#!/usr/bin/env -S scala-cli shebang

//> using scala "3.4.3"
//> using dep "org.vastblue::unifile:0.4.1"

import vastblue.unifile.*

// display the native path and lines.size of /etc/fstab
// mapped to "C:\msys64\etc\fstab" in Windows
val p = Paths.get("/etc/fstab")
printf("%s\n", p.posx)
printf("env: %-10s| %-22s | %d lines\n", uname("-o"), p.posx, p.lines.size)

Output of the previous example script on various platforms:

Linux Mint # env: GNU/Linux | shellRoot: /           | /etc/fstab            | 21 lines
Darwin     # env: Darwin    | shellRoot: /           | /etc/fstab            | 0 lines
WSL Ubuntu # env: GNU/Linux | shellRoot: /           | /etc/fstab            | 6 lines
Cygwin64   # env: Cygwin    | shellRoot: C:/cygwin64 | C:/cygwin64/etc/fstab | 24 lines
Msys64     # env: Msys      | shellRoot: C:/msys64/  | C:/msys64/etc/fstab   | 22 lines

Note that on Darwin, there is no /etc/fstab file, so the Path#lines extension returns Nil.

Setup

• Windows: install one of the following:
  • MSYS64
  • CYGWIN64
  • WSL
  • Git Bash
• Linux: required packages:
  • sudo apt install coreutils
• Darwin/OSX:
  • brew install coreutils

Tips for Writing Portable Scala Scripts

Most portability issues concern the differences between Windows jvms and most others. Things that maximize the odds of your script running everywhere:

• prefer scala 3
• always use forward slashes in literal path Strings except when displaying output
• in Windows
  • represent paths internally with forward slashes
  • minimize reference to drive letters
    • drive letter not needed for paths on the current working drive (often C:)
    • to access disks other than the working drive, mount them via /etc/fstab
    • vastblue.unifile.Paths.get() parses both posix and Windows filesystem paths
• Avoid using java.nio.File.separator or sys.props("line.separator") to parse input
• (they are safe to use on output.)
• When parsing input text, be OS-agnostic:
  • split Strings with internal newlines using "(\r)?\n"
• create java.nio.file.Path objects in either of two ways:
  • `vastblue.file.Paths.get("/etc/fstab")
  • "/etc/fstab".path // uses vastblue.file.Paths.get()`