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Nguyễn Nhật Nam
2023-07-25 18:47:32 +08:00
committed by GitHub

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@@ -232,10 +232,10 @@ declare -l # uppercase values in the variable are converted to
declare -A # makes it an associative array
${varname:-word} # if varname exists and isn't null, return its value; otherwise return word
${varname:word} # if varname exists and isn't null, return its value; otherwise return word
${varname:=word} # if varname exists and isn't null, return its value; otherwise set it word and then return its value
${varname:?message} # if varname exists and isn't null, return its value; otherwise print varname, followed by message and abort the current command or script
${varname:+word} # if varname exists and isn't null, return word; otherwise return null
${varname:offset} # performs substring expansion. It returns the substring of $varname starting at offset to the end
${varname:offset:length} # performs substring expansion. It returns the substring of $varname starting at offset and up to length characters
${variable#pattern} # if the pattern matches the beginning of the variable's value, delete the shortest part that matches and return the rest