Description of use of regular expressions in Shell if

The IF statement in the shell needs to make a regular judgment and check the grammatical records.

The code is as follows	Copy Code
Datepattern= "^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$" if [["$STARTDATE" =~ $DATEPATTERN]] && [[$ENDDATE =~ $DATEPATTERN]]; Then: Else echo "date format is invalid!" Exit Fi

Regular expressions that are commonly used

1, if [["$file" =~ ' start ']]
2, or if [["$file" =~ "Start"]]

Example:

The code is as follows	Copy Code
#!/usr/bin/ksh File= "10start11.s" if [["$file" =~ "Start"]] Then echo "Success" Else echo "Failed" Fi

only bash supports [[

Ksh should not support regular in test, use awk grep sed and other tools to implement it

code is as follows	copy code
flag= ' echo $file |awk '/start/' If [' $flag ' = ' '];then  echo ' success ' Else  echo ' failed ' Fi