What Vim command to use to delete all text after a certain character on every line of a file?

:%s/^\v([^|]+\|[^|]+)\|.*$/\1/

You can also record a macro:

qq02f|Djq

and then you will be able to play it with 100@q to run the macro on the next 100 lines.

Macro explanation:

• qq: starts macro recording;
• 0: goes to the first character of the line;
• 2f|: finds the second occurrence of the | character on the line;
• D: deletes the text after the current position to the end of the line;
• j: goes to the next line;
• q: ends macro recording.

If you don't have to use Vim, another alternative would be the unix cut command:

cut -d '|' -f 1-2 file > out.file