Learning AWK Programming

Concatenation using alternation operator within parentheses

Parentheses can be used to concatenate regular expressions using the '|' alternation operator. In this, we simply place two or more regular expressions separated using the alternation operator pipe, '|', within parentheses to match any of them. For example, in the given example we print lines with the Jane, Emily, Ana, or Victor employee name from the emp.dat file, as follows:

$ awk '/(Jane|Emily|Ana|Victor)/{ print }' emp.dat

The output on execution of the preceding code is as follows:

Jane    Kaur    9837432312  [e-mail]      F   hr      1800Ana     Khanna  9856422312  [e-mail]    F   Ops     2700Victor  Sharma  8826567898  [e-mail]    M   Ops     2500Emily   Kaur    8826175812  [e-mail]     F   Ops     2100