Shell script Programming Shell string

1. Limitations of single-quote strings:

• Any character in a single quotation mark is output as is, and the variable in the single-quote string is not valid;
• Single quotation marks cannot appear in single quote strings (not after using escape characters for single quotes).

2. Advantages of double quotes:

• You can have variables in double quotes.
• Escape characters can appear in double quotes

3. Stitching strings:

4. Get the string length:

5. Extract substrings:

6. Look up substrings:

Shell script Programming Shell string