commit b84a808c43f859caff7675b7d4f102f4b7088fe3
Author: Nikolay Puzanov <np@embddr.com>
Date:   Mon Mar 1 17:39:21 2021 +0300

    Initial commit

diff --git a/LICENSE b/LICENSE
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+++ b/LICENSE
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+MIT License
+
+Copyright (c) 2021 punzik
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/Makefile b/Makefile
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+++ b/Makefile
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+all: nbackbright.nim
+	nim c -d:release --opt:size nbackbright.nim
+
+clean:
+	rm -rf nbackbright
diff --git a/README.md b/README.md
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+Simple tool for backlight brightness control. For build from source needs
+[Nim](https://nim-lang.org/) language compiler.
+
+Usage: `nbackbright <percent>`, where `<percent>` is a percentage of brightness
+changing.
+
+For example: `nbackbright -10` decrease brightness by 10%.
diff --git a/nbackbright.nim b/nbackbright.nim
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+++ b/nbackbright.nim
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+import os
+import streams
+import strutils
+
+const
+  BL_SYS_DIR = "/sys/class/backlight"
+
+proc change_brightness(percent: int) =
+  if dirExists(BL_SYS_DIR):
+    for kind, path in walkDir(BL_SYS_DIR):
+      let
+        br_file = path & "/brightness"
+        mb_file = path & "/max_brightness"
+      if fileExists(br_file) and fileExists(mb_file):
+        try:
+          let br_stream = openFileStream(br_file)
+          let br = parseInt(br_stream.readLine())
+          br_stream.close()
+
+          let mb_stream = openFileStream(mb_file)
+          let mb = parseInt(mb_stream.readLine())
+          mb_stream.close()
+
+          var new_br = int(float(br) + float(mb) / 100.0 * float(percent))
+          if new_br < 0: new_br = 0
+          if new_br > mb: new_br = mb
+
+          let br_write = openFileStream(br_file, fmWrite)
+          br_write.writeLine(new_br)
+          br_write.close()
+        except:
+          echo "Fail to interact with ", br_file
+
+when isMainModule:
+  if paramCount() > 0:
+    let percent = parseInt(paramStr(1))
+    change_brightness(percent)