Match the string "hello" anywhere on a line:
/hello/
Match the string "hello" at the start of a line:
/^hello/
Match the string "hello" at the end of a line:
/hello$/
Match a line containing only the string "hello":
/^hello$/
Match all trailing blanks (including zero) on a line:
/ *$/
Match all characters (including zero) on a line:
/^.*$/
Match a number like "3", "862", etc:
/[0-9][0-9]*/
Match a C language identifier:
/[a-z_][a-z_0-9]*/
Match a digit in column ten:
/@(10)[0-9]/
Match an empty line:
/^^$/
Match a line containing only blanks:
/^^*$/
Match a line starting with a period followed by a name (such as a command in the QNX2 DOC markup language):
/^\.[a-z][a-z]*/