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 "${#var}"
10
linyb@DESKTOP-UOO833B:~$
删去左右两边的特点字符
linyb@DESKTOP-UOO833B:~$ path="/etc/rc0.d/K20openbsd-inetd"
linyb@DESKTOP-UOO833B:~$ echo "${
27
linyb@DESKTOP-UOO833B:~$ echo "${path}"
/etc/rc0.d/K20openbsd-inetd
//删去左边的字符串
linyb@DESKTOP-UOO833B:~$ level=${path
linyb@DESKTOP-UOO833B:~$ echo "${level}"
20openbsd-inetd
//删去右边的字符串
linyb@DESKTOP-UOO833B:~$ level=${level%%[a-zA-Z]*}
linyb@DESKTOP-UOO833B:~$ echo "${level}"
20
linyb@DESKTOP-UOO833B:~$