Question

Unix / Linux

16.

Regular Expression:

Given the following regular expression, provide a description of the intended match.

^[^A-Z]

17.

Regular Expression:

Given the following regular expression, provide a description of the intended match.

[^^!]

18.

Regular Expression:

Given the following regular expression, provide a description of the intended match.

^.\{72\}$

19.

Regular Expression:

Given the following regular expression, provide a description of the intended match.

[A-Za-z0-9]

20.

Regular Expression:

Given the following regular expression, provide a description of the intended match. [There's a single space character inside the first square bracket pair.]

[ ][A-Za-z]\{1,\}$

Answer 1

16. [^ ] means a single character that isn't a part of this group.

Hence, [^ A-Z] means no capital letters should be present.

^[] means this pattern should be included in the beginning of the line.

Hence, ^[^A-Z] means no capital letter should be present in the beginning of the line.

17. [^] means anything except the characters or symbols enclosed.

hence, [^^!] means any character other than ^ or ! is acceptable.

18. ^.\{72\}$ means to group all the lines which are exactly 72 characters wide.

19. [ ] means a single character present within the group.

hence, [A-Za-z0-9] means any character or numeric value is acceptable as a single character.

20. It means if you want to replace these relating character to something else.

It can be manipulated in sed command as

$ sed 's/[][A-za-z]\{1,\}$/replace/'

The alphabets should be replaced by the specified characters. Any combination of a space with an alphabet should be replaced with the specified digits.