Cross Platform Bash Snippet for Linux, WSL 1, Cygwin, Msys, and GitBash.

x-platform.sh

#!/bin/bash
# shebang added only to appease shellcheck

# Cross-platform for bash.
# Worry less about when writting a script that must run on Windows and Linux.
# Meant to be used with "source" command in scripts or .bashrc/.zshrc

export USER="${USER:-${USERNAME:-$(whoami)}}"
export USERNAME="${USERNAME:-$USER}"
export HOSTNAME="${HOSTNAME:-${MACHINENAME:-$(hostname)}}"
# Partial x-platform support for: cygpath, xdg-open, winpty, sudo, cmd
if [[ "$(uname -s)" == "Linux" ]]; then
    if [[ "$(uname -r)" == *-Microsoft ]]; then
        # WSL 1
        if ! [[ -d /c ]]; then
            echo "/c must be mounted to /mnt/c"
            exit 1
        fi
        export USERPROFILE="${USERPROFILE:-/c/Users/$USER}"
        xdg-open() { cmd /c start "$1"; }
        if ! command -v cmd &>/dev/null; then
            cmd() { /c/Windows/System32/cmd.exe "$@"; }
        fi
        if ! command -v cygpath &>/dev/null; then
            if command -v wslpath &>/dev/null; then
                cygpath() { wslpath "$@"; }
            else
                cygpath() {
                    if [[ "$1" == "-w" ]]; then
                        shift
                        readlink -f "$@" | \
                            sed -r '/^(\/mnt)?\/[a-z]\b/ { s|/^(\/mnt)?\/([a-z])\b|\U\2:|; s|/|\\|g; }'
                    else
                        printf "%s\n" "$@" | sed -r 's|^(.):|/\L\1|; s|\\|/|g;'
                    fi
                }
            fi
        fi
        # Bug workaround
        nice() {
            if [[ "$1" == "-n" ]]; then shift; shift; fi
            "$@"
        }
        export -f nice
        renice() { :; }
        export -f renice
    else
        # Real Linux
        if [[ -z "${SSH_CONNECTION:-}" ]]; then
            xdg-open() { w3m "$1"; }
        fi
        export USERPROFILE="${USERPROFILE:-$HOME}"
        cmd() { shift; "$@"; }
        cygpath() {
            if [[ "$1" == "-w" ]]; then shift; fi
            readlink -f "$1"
        }
        
        if command -v podman &>/dev/null && ! command -v docker &>/dev/null; then
            docker() {
                PODMAN_USERNS=keep-id podman "$@"
            }
        fi
    fi
    winpty() { "$@"; }
else
    # Msys / Cygwin
    xdg-open() { cmd /c start "$1"; }
    sudo() { "$@"; }
    export MSYS_NO_PATHCONV=1
    export MSYS2_ARG_CONV_EXCL='*'
    export COMPOSE_CONVERT_WINDOWS_PATHS=1
    if command -v docker &>/dev/null; then
        # voodoo magic to make the tty work correctly
        docker() {
            realdocker="$(command -v docker)"
            # --tty or -t requires winpty
            #shellcheck disable=SC2140,SC1001,SC2068,SC2145,SC2027
            if printf "%s\0" "$@" | grep -ZE '^--tty|^-[^-].*t|^-t.*'; then
                winpty /bin/bash -c "xargs -0a <(printf "%s\0" "$@") '$realdocker'"
            else
                "$realdocker" "$@"
            fi
        }
        export docker
    fi
fi

if [[ -n "$TIMEFORMAT" ]]; then
    export TIME="$TIMEFORMAT"
    export TIMEFMT="$TIMEFORMAT"
fi

# If an ssh connection, connect X back to the host (a MS-Windows X server)
[ -z "$SSH_CLIENT" ] || export DISPLAY="${SSH_CLIENT/ */}:0"

TODO:

• kill() - Use taskkill /f /pid for native windows processes and command kill "$@" for msys processs.
• curl - If Msys, convert paths with cygpath -w
• curl - wintpy vs password prompt
• Test with WSL 2
• MacOS support

I no longer work with Windows, so this isn't maintained much. However, I may get a Mac soon, so I may add support for OSX.

$ diff -u x-platform.sh.orig x-platform.sh
--- x-platform.sh.orig  2020-02-23 08:42:55.487752100 -0800
+++ x-platform.sh       2020-02-23 15:57:36.538387800 -0800
@@ -27,12 +27,12 @@
                         shift
                         readlink -f "$@" | \
                             sed -r '/^(\/mnt)?\/[a-z]\b/ { s|/^(\/mnt)?\/([a-z])\b|\U\2:|; s|/|\\|g; }'
-                    elsif
+                    else
                         printf "%s\n" "$@" | sed -r 's|^(.):|/\L\1|; s|\\|/|g;'
                     fi
                 }
-            }
-        }
+            fi
+        fi
         nice() {
             if [[ "$1" == "-n" ]]; then shift; shift; fi
             "$@"
@@ -66,7 +66,7 @@
             realdocker="$(which docker)"
             # --tty or -t requires winpty
             if printf "%s\0" "$@" | grep -ZE '^--tty|^-[^-].*t|^-t.*'; then
-                winpty /bin/bash -c "xargs -0a <(printf "%s\0" "$@") '$realdocker'"
+                command winpty xargs -0a <(printf "%s\0" "$@") "$realdocker"
             else
                 "$realdocker" "$@"
             fi

@jmeubank Thanks for the fixes.

I can't remember why, but bash -c "xargs..." is necessary as is. It fixes some weirdness with winpty and Windows.