Shell Scripting

Scripting

• #!/bin/bash - Tell what shell to use to execute the script if flagged as executable.
  • If not executable, specify the shell to run it. bash <script_name>
  • Add flag with chmod u+x <script_name>
• Script must be in the PATH variable to work. pwd ; echo $PATH
• # - Comment
• echo - Print to screen (-e = allow formatting flags)
  • \b - Move cursor back one space
  • \c - No new line after print
  • \f <number> - Force a specific horizontal location on the next line
  • \n - Newline
  • \t - Tab
• Use history <number> > <script_name> to stub out a script.
• Time formats:
• %d = day, %y = 2-digit year, etc.
• $1-$9 are CLI arguments at runtime
• read <variable_name> will prompt a user for input.
  • Used in script with $varible_name
• sh -x <script_name> displays each line for debugging
• UNIX-Loops & UNIX-Conditionals