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

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Last updated: 2023-04-11