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Bash Scripting

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Bash Scripting

Variables

  • Defining variables: variable_name=34
    • Storing the output of a command: variable=$(pwd)
    • There should be no space on either side of =.
  • We refer variables using $variable_name
Always name you variables in lower case.

In general upper case variable names mean they are defined by the system. Like $USER or $HOME

  • Double quotes are used for variable expansion, single quotes treats the strings as is without any expansion.

Math Operations

  • Arithmetic operation: expr 80 + 10, expr 80 - 10, expr 80 / 10
  • * won't work for multiplication since * is a wild card in bash.
    • expr 80 \* 10
  • Using variables: expr $var1 + $var2

Exit codes

  • Status of the last command: echo $?

TODOs

  • Arrays in bash
  • Inputs in bash
  • EOF in Bash

References


Last updated: 2022-11-28