<note>
  * [[http://linux.vbird.org/linux_basic/0320bash.php|第十章、認識與學習BASH]]
  * [[http://people.cs.nctu.edu.tw/~chenwj/slide/SA/ShellProgramming.new.pdf|Shell and Shell Programming]]
  * [[http://www.covingtoninnovations.com/mc/winforunix.html|Windows for UNIX Users]]
  * [[http://www.lemoda.net/windows/windows2unix/windows2unix.html|Windows and Unix command line equivalents]]
</note>

<code bash>
# 以空白做區分，取出第六欄
$ grep TraceInit debug_panic_427.txt | cut -d " " -f 6
# 取匹配後的下一行
$ grep -A1 foo bar.txt
# 將 stdin 當作後續指令的輸入
$ echo "foo" | xargs -0 -I {} rm -f {}
</code>

  * [[http://www.linuxtutorialblog.com/post/tutorial-conditions-in-bash-scripting-if-statements|Tutorial: Conditions in bash scripting (if statements)]]
  * [[http://www.linuxjournal.com/content/bash-regular-expressions|Bash Regular Expressions]]

<code bash>
if [ $(echo "$max < $val" | bc) -eq 1 ] ; then
  # DO SOMETHING
else
  # DO SOMETHING
fi
</code>
  * [[http://unstableme.blogspot.com/2008/06/bash-float-comparison-bc.html|Bash float comparison - bc]]
  * [[http://stackoverflow.com/questions/10383529/can-i-replace-the-array-name-in-a-bash-script|Can I replace the array name in a bash script?]]
    * [[http://www.linuxjournal.com/content/tech-tip-dereference-variable-names-inside-bash-functions|Tech Tip: Dereference Variable Names Inside Bash Functions]] 
  * [[http://www.linuxjournal.com/content/bash-associative-arrays|Bash Associative Arrays]]
  * [[http://insights-into-software.blogspot.com/2010/03/elegant-parallel-processes-in-bash.html|Elegant parallel processes in bash]]
  * [[http://pebblesinthesand.wordpress.com/2008/05/22/a-srcipt-for-running-processes-in-parallel-in-bash/|A srcipt for running processes in parallel in Bash]]
  * [[http://www.linuxtopia.org/online_books/advanced_bash_scripting_guide/subshells.html|Chapter 20. Subshells]]

====== 範例 ======
  * 計算目錄下各個目的檔所佔的 ROM 大小 (.text + .data)。<code bash>
$ ls | xargs arm-none-eabi-size.exe | sed '1d' | awk '{sum = $1 + $2}; {print sum}'
</code>
    * [[http://unix.stackexchange.com/questions/96226/delete-first-line-of-a-file|Delete First line of a file]]
    * [[http://www.unix.com/unix-for-dummies-questions-and-answers/82810-how-get-nth-line-file-usuing-commands.html|How to get nth line from a file usuing commands]]
    * [[http://www.liamdelahunty.com/tips/linux_ls_awk_totals.php|Linux - Sum using awk]]
  * 修改目錄下 (包含子目錄) 檔案的權限。<code bash>
$ find . -type f -exec chmod 644 {} +
</code>
    * [[http://askubuntu.com/questions/58467/chmod-files-only-in-all-subdirectories|chmod files only in all subdirectories]]
  * 批次修改目錄下的所有檔名。<code>
# 將檔名中帶有 foo 的字串，替換成 bar。
$ for filename in *foo*; do mv "$filename" "${filename//foo/bar}"; done
</code>
    * [[http://www.peteryu.ca/tutorials/shellscripting/batch_rename|Batch rename files by finding and replacing terms in the filename]]
====== 常用工具 ======
  * [[wp>cut]]
  * [[wp>sed]]
  * [[wp>awk]]
    * [[http://www.cyberciti.biz/faq/bash-scripting-using-awk/|How To Use awk In Bash Scripting]]
  * [[wp>xargs]]
    * [[https://sidvind.com/wiki/Xargs_by_example|Xargs by example]]
    * [[http://www.cyberciti.biz/faq/linux-unix-bsd-xargs-construct-argument-lists-utility/|xargs: How To Control and Use Command Line Arguments]]
====== Q & A ======
  * [[http://www.linuxdevcenter.com/pub/a/linux/lpt/09_22.html|xargs: Problems with Spaces and Newlines]]
====== 外部連結 ======
  * [[http://tldp.org/LDP/Bash-Beginners-Guide/html/index.html|Bash Guide for Beginners]]
  * [[http://tldp.org/LDP/abs/html/index.html|Advanced Bash-Scripting Guide]]
  * [[http://www.ibm.com/developerworks/library/l-bash.html|Bash by example]]
  * [[http://wiki.bash-hackers.org/syntax/quoting|Quotes and escaping]]
    * 用雙引號將 Windows 路徑包起來，以當成字串處理。