Echo one line from a file in Linux

Output a specific line from a text file with awk.

awk 'NR==1' filename

Example
In this example we have mysql dump file with a syntax error on line 15588. That's a big file, so we don't want to fuss about in a text editor looking for it.

$ awk 'NR==15588' mydatabase.sql 
Warning: Using a password on the command line interface can be insecure.

Reading the offending line directly shows us the Drupal Backup and Migrate module is causing mysql warnings to be written to the dump file, which causes the fatal import errors.