= Shell Logic =

<<TableOfContents>>

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== Conditional Logic ==

{{{
if [ TEST ]; then
  echo "TEST is true"
elif grep /path/to/file --fixed-strings foo >/dev/null; then
  echo "TEST is false and '/path/to/file' contains 'foo'"
else
  echo "TEST is false and '/path/to/file' does not contain 'foo'"
fi
}}}

[[Shell/Test|Shell tests]] are typically used as the condition (as seen above), but any command that sets the exit code in the expected pattern (zero for true, non-zero for false; as seen above with `grep(1)`) can be used.

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== Conditional Commands ==

To execute a command conditionally after another command, try:

{{{
true && echo "This only executes because the first command set an exit code of 0"

false || echo "This only executes because the first command set an exit code of 1"
}}}

These operators have equal precedence.

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== Case Switching Logic ==

{{{
case $INPUT_STRING in
  y)
    echo "Proceeding..."
    ;;
  n)
    echo "Quitting..."
    ;;
  *)
    echo "Please enter y or n only"
    ;;
esac
}}}



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CategoryRicottone