shell中处理字符串

计算字符串的个数

linyb@DESKTOP-UOO833B:~$ var="apple tree"linyb@DESKTOP-UOO833B:~$ echo "${#var}"10linyb@DESKTOP-UOO833B:~$

删去左右两边的特点字符

linyb@DESKTOP-UOO833B:~$ path="/etc/rc0.d/K20openbsd-inetd"linyb@DESKTOP-UOO833B:~$ echo "${#path}"27linyb@DESKTOP-UOO833B:~$ echo "${path}"/etc/rc0.d/K20openbsd-inetd//删去左边的字符串linyb@DESKTOP-UOO833B:~$ level=${path#/etc/rc[0-9].d/[SK]}linyb@DESKTOP-UOO833B:~$ echo "${level}"20openbsd-inetd//删去右边的字符串linyb@DESKTOP-UOO833B:~$ level=${level%%[a-zA-Z]*}linyb@DESKTOP-UOO833B:~$ echo "${level}"20linyb@DESKTOP-UOO833B:~$