在逐个命令的基础上为bash完成设置不区分大小写

简单的解决方案：首先将单词列表和输入标记翻译为全小写.
注意：如果所有完成都变为全小写,则这只是一个选项.

complete_lower() {

    local token=${COMP_WORDS[$COMP_CWORD]}
    local words=$( db --complete $COMP_CWORD "${COMP_WORDS[@]}" )

    # Translate both the word list and the token to all-lowercase.
    local wordsLower=$( printf %s "$words" | tr [:upper:] [:lower:] )
    local tokenLower=$( printf %s "$token" | tr [:upper:] [:lower:] )

    COMPREPLY=($(compgen -W "$wordsLower" -- "$tokenLower"))   
}

更好,但更精细的解决方案：滚动自己的,不区分大小写的匹配逻辑：

complete_custommatch() {

    local token=${COMP_WORDS[$COMP_CWORD]}
    local words=$( db --complete $COMP_CWORD "${COMP_WORDS[@]}" )

    # Turn case-insensitive matching temporarily on,if necessary.
    local nocasematchWasOff=0
    shopt nocasematch >/dev/null || nocasematchWasOff=1
    (( nocasematchWasOff )) && shopt -s nocasematch

    # Loop over words in list and search for case-insensitive prefix match.
    local w matches=()
    for w in $words; do
        if [[ "$w" == "$token"* ]]; then matches+=("$w"); fi
    done

    # Restore state of 'nocasematch' option,if necessary.
    (( nocasematchWasOff )) && shopt -u nocasematch

    COMPREPLY=("${matches[@]}")
}