问题
I've been trying to make this thing work for a couple of hours but I can't get it to work :
if [ "$P" = "SFTP" -a "$PORT" != "22" ] || [ "$P" = "FTPS" && [ "$PORT" != "990" -a "$PORT" != "21" ] ] ; then
Can someone help me ? I know that multiple conditions can be written like this :
if [ "$P" = "SFTP" ] && [ "$PORT" != "22" ]; then
but how can I imbricate theses conditions like in my first example?
回答1:
You can't nest expressions in single brackets. It should be written like this:
if [ "$P" = "SFTP" -a "$PORT" != "22" ] || [ "$P" = "FTPS" -a "$PORT" != "990" -a "$PORT" != "21" ] ; then
This can be written as a single expressions as:
if [ \( "$P" = "SFTP" -a "$PORT" != "22" \) -o \( "$P" = "FTPS" -a "$PORT" != "990" -a "$PORT" != "21" \) ] ; then
although is is not fully compatible with all shells.
Since you are using bash, you can use double brackets to make the command more readable:
if [[ ( $P = "SFTP" && $PORT != "22" ) || ( $P = "FTPS" && $PORT != "990" && $PORT != "21" ) ]] ; then
来源：https://stackoverflow.com/questions/18974788/bash-if-multiple-conditions