Knowledge accumulation in Linux scripts

1. Take the/etc/hotplug.d/button/00-button in OpenWrt as an example

. /lib/functions.shdo_button () {Local button----defining local variablesLocal actionLocal handlerLocal minLocal MaxConfig_get buttonConfig_get Action ActionConfig_get Handler $ handlerConfig_get min $ minConfig_get Max $ max["$ACTION" = "$action"-a "$BUTTON" = "$button"-a-n "$handler"] && {[-Z "$min"-o-z "$max"] && eval $handler[-N "$min"-a-n "$max"] && {[$min-le $SEEN-a $max-ge $SEEN] && eval $handler}}

Explain:

[]---Judge the condition, if the result inside is true, then perform the subsequent processing

=---values are equal

-A logic and

Whether the-n variable exists

Whether the-Z variable does not exist

-O Logic or

-le Less than & equal

-ge great than & equal  

}config_load Systemconfig_foreach Do_button button

Knowledge accumulation in Linux scripts