Fix erroneous function call on NetBSD

Some non-Linux systems do not have a `/sys/` directory. Therefore,
check it only if we are in a Linux system.

Fixes #19

README.org

@@ -22,6 +22,7 @@ macOS. PR are welcome if you want to fix that!
 * Table of Contents                                                :TOC_2_gh:
 - [[#introduction][Introduction]]
 - [[#recent-breaking-changes][Recent Breaking Changes]]
+  - [[#081][~0.8.1~]]
   - [[#070][~0.7.0~]]
 - [[#installation][Installation]]
 - [[#customizing][Customizing]]
@@ -33,6 +34,11 @@ macOS. PR are welcome if you want to fix that!
 - [[#license][License]]
 
 * Recent Breaking Changes
+** ~0.8.1~
+Version ~0.8.1~ removes the optional argument ~REMOTE~ from
+~eshell-info-banner--executable-find~. It now only acts according to the
+user’s preference set with ~eshell-info-banner-tramp-aware~.
+
 ** ~0.7.0~
 Version ~0.7.0~ renames several functions to conform with the Elisp
 Coding Conventions.

eshell-info-banner.el

@@ -2,7 +2,7 @@
 
 ;; Author: Lucien Cartier-Tilet <lucien@phundrak.com>
 ;; Maintainer: Lucien Cartier-Tilet <lucien@phundrak.com>
-;; Version: 0.8.0
+;; Version: 0.8.4
 ;; Package-Requires: ((emacs "25.1") (f "0.20") (s "1"))
 ;; Homepage: https://github.com/Phundrak/eshell-info-banner.el
 
@@ -65,7 +65,11 @@
 
 (eval-when-compile
   (defconst eshell-info-banner--macos-versions
-    '(("10.4"  . "Mac OS X Tiger")
+    '(("10.0"  . "Mac OS X Cheetah")
+      ("10.1"  . "Mac OS X Puma")
+      ("10.2"  . "Mac OS X Jaguar")
+      ("10.3"  . "Mac OS X Panther")
+      ("10.4"  . "Mac OS X Tiger")
       ("10.5"  . "Mac OS X Leopard")
       ("10.6"  . "Mac OS X Snow Leopard")
       ("10.7"  . "Mac OS X Lion")
@@ -84,9 +88,15 @@
       ("11.3"  . "macOS Big Sur")
       ("11.4"  . "macOS Big Sur")
       ("11.5"  . "macOS Big Sur")
-      ("11.6"  . "macOS Big Sur"))
+      ("11.6"  . "macOS Big Sur")
+      ("12.0"  . "macOS Monterey")
+      ("12.1"  . "macOS Monterey")
+      ("12.2"  . "macOS Monterey"))
     "Versions of OSX and macOS and their name."))
 
+(defconst eshell-info-banner--posix-shells '("bash" "zsh" "sh")
+  "List of POSIX-compliant shells to run external commands through.")
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
                                         ;           Custom variables          ;
@@ -140,18 +150,18 @@
   :type 'list
   :version "0.3.0")
 
-(defun eshell-info-banner--executable-find (program &optional remote)
-  "Find PROGRAM executable, possibly on a REMOTE machine.
+(defun eshell-info-banner--executable-find (program)
+  "Find PROGRAM executable, possibly on a remote machine.
 This is a wrapper around `executable-find' in order to avoid
 issues with older versions of the functions only accepting one
-argument."
+argument. `executable-find'’s remote argument has the value of
+`eshell-info-banner-tramp-aware'."
   (if (version< emacs-version "27.1")
-      (let ((default-directory (if (and eshell-info-banner-tramp-aware
-                                        remote)
+      (let ((default-directory (if eshell-info-banner-tramp-aware
                                    default-directory
                                  "~")))
         (executable-find program))
-    (executable-find program remote)))
+    (executable-find program eshell-info-banner-tramp-aware)))
 
 (defcustom eshell-info-banner-duf-executable "duf"
   "Path to the `duf' executable."
@@ -215,13 +225,21 @@ argument."
 (defun eshell-info-banner--shell-command-to-string (command)
   "Execute shell command COMMAND and return its output as a string.
 Ensures the command is ran with LANG=C."
-  (shell-command-to-string (format "LANG=C %s" command)))
+  (let ((shell (or (seq-find (lambda (shell)
+                              (eshell-info-banner--executable-find shell))
+                            eshell-info-banner--posix-shells)
+                  "sh")))
+    (with-temp-buffer
+      (call-process shell nil t nil "-c" (concat "LANG=C " command))
+      (buffer-string))))
 
 (defun eshell-info-banner--progress-bar-without-prefix (bar-length used total &optional newline)
   "Display a progress bar without its prefix.
 Display a progress bar of BAR-LENGTH length, followed by an
 indication of how full the memory is with a human readable USED
-and TOTAL size."
+and TOTAL size.
+Optional argument NEWLINE: Whether to output a newline at the end
+of the progress bar."
   (let ((percentage (if (= used 0)
                         0
                       (/ (* 100 used) total))))
@@ -451,19 +469,80 @@ For TEXT-PADDING and BAR-LENGTH, see the documentation of
                         "\n"
                         t)))
 
-(defun eshell-info-banner--get-memory-unix ()
-  "Get memory usage for UNIX systems.
-Compatible with Darwin and FreeBSD at least."
-  (let* ((command-to-mem (lambda (command)
-                           (string-to-number
+(defun eshell-info-banner--get-memory-unix-command-to-mem (command)
+  "Get the output of COMMAND corresponding to memory information.
+This function is to be only used on platforms which support sysctl."
+  (string-to-number
+   (s-trim
+    (car (last
+          (split-string (eshell-info-banner--shell-command-to-string command)
+                        " "
+                        t))))))
+
+(defun eshell-info-banner--get-memory-netbsd ()
+  "Get memory usage for NetBSD systems.
+See `eshell-info-banner--get-memory'."
+  (let* ((total (eshell-info-banner--get-memory-unix-command-to-mem "sysctl hw.physmem64"))
+         (used  (- total
+                   (* 1024 (string-to-number
                             (s-trim
-                             (cadr
-                              (split-string (eshell-info-banner--shell-command-to-string command)
-                                            " "
-                                            t)))))))
-    `(("RAM"
-       ,(apply command-to-mem '("sysctl hw.physmem"))
-       ,(apply command-to-mem '("sysctl hw.usermem"))))))
+                             (with-temp-buffer
+                               (insert-file-contents-literally "/proc/meminfo")
+                               (save-match-data
+                                 (string-match (rx bol
+                                                   "MemFree:"
+                                                   (* blank)
+                                                   (group (+ digit))
+                                                   (* blank)
+                                                   "kB")
+                                               (buffer-string))
+                                 (substring-no-properties (buffer-string)
+                                                          (match-beginning 1)
+                                                          (match-end 1))))))))))
+    `(("RAM" ,total ,used))))
+
+(defun eshell-info-banner--get-memory-darwin ()
+  "Get memory usage for Darwin systems.
+See `eshell-info-banner--get-memory'."
+  (let* ((total  (eshell-info-banner--get-memory-unix-command-to-mem "sysctl -n hw.memsize"))
+         (vmstat (with-temp-buffer
+                   (call-process "vm_stat" nil t nil)
+                   (buffer-string)))
+         (wired  (save-match-data
+                   (string-match (rx " wired" (* (not digit)) (+ blank) (group (+ digit)) ".")
+                                 vmstat)
+                   (* 1024 4
+                      (string-to-number (substring-no-properties vmstat
+                                                                 (match-beginning 1)
+                                                                 (match-end 1))))))
+         (active (save-match-data
+                   (string-match (rx " active" (* (not digit)) (+ blank) (group (+ digit)) ".")
+                                 vmstat)
+                   (* 1024 4
+                      (string-to-number (substring-no-properties vmstat
+                                                                 (match-beginning 1)
+                                                                 (match-end 1))))))
+         (compressed (save-match-data
+                       (if (string-match (rx " occupied" (* (not digit)) (+ blank) (group (+ digit)) ".")
+                                         vmstat)
+                           (* 1024 4
+                              (string-to-number (substring-no-properties vmstat
+                                                                         (match-beginning 1)
+                                                                         (match-end 1))))
+                         0))))
+    `(("RAM" ,total ,(+ wired active compressed)))))
+
+(defun eshell-info-banner--get-memory-unix ()
+  "Get memory usage for UNIX systems."
+  (cond ((and (equal system-type 'berkeley-unix)
+              (string-match-p "NetBSD" (eshell-info-banner--shell-command-to-string "uname")))
+         (eshell-info-banner--get-memory-netbsd))
+        ((equal system-type 'darwin)
+         (eshell-info-banner--get-memory-darwin))
+        (t
+         (let* ((total (eshell-info-banner--get-memory-unix-command-to-mem "sysctl hw.physmem"))
+                (used  (eshell-info-banner--get-memory-unix-command-to-mem "sysctl hw.usermem")))
+           `(("RAM" ,total ,used))))))
 
 (defun eshell-info-banner--get-memory-windows ()
   "Get memory usage for Window."
@@ -580,7 +659,9 @@ The usage of `eshell-info-banner-warning-percentage' and
 thought of as the “percentage of discharge” of the computer.
 Thus, setting the warning at 75% will be translated as showing
 the warning face with a battery level of 25% or less."
-  (let ((battery-level (when (file-readable-p "/sys/") (battery))))
+  (let ((battery-level (unless (and (equal system-type 'gnu/linux)
+                                    (not (file-readable-p "/sys/")))
+                         (battery))))
     (if (or (null battery-level)
             (string= battery-level "Battery status not available")
             (string-match-p (regexp-quote "N/A") battery-level))
@@ -662,7 +743,7 @@ If RELEASE-FILE is nil, use '/etc/os-release'."
                    (insert-file-contents (concat prefix "/bedrock/etc/bedrock-release"))
                    (buffer-string))))
         ;; Proxmox
-        ((eshell-info-banner--executable-find "pveversion" eshell-info-banner-tramp-aware)
+        ((eshell-info-banner--executable-find "pveversion")
          (let ((distro (eshell-info-banner--shell-command-to-string "pveversion")))
            (save-match-data
              (string-match "/\\([^/]+\\)/" distro)
@@ -670,9 +751,9 @@ If RELEASE-FILE is nil, use '/etc/os-release'."
                      (substring-no-properties distro
                                               (match-beginning 1)
                                               (match-end 1))))))
-        ((eshell-info-banner--executable-find "hostnamectl" eshell-info-banner-tramp-aware)
+        ((eshell-info-banner--executable-find "hostnamectl")
          (eshell-info-banner--get-os-information-from-hostnamectl))
-        ((eshell-info-banner--executable-find "lsb_release" eshell-info-banner-tramp-aware)
+        ((eshell-info-banner--executable-find "lsb_release")
          (eshell-info-banner--get-os-information-from-lsb-release))
         ((file-exists-p (concat prefix "/etc/os-release"))
          (eshell-info-banner--get-os-information-from-release-file))