How to truncate text lines to N characters maximum? [duplicate]

Question

Given a text file, or the output of a command, how can I truncate it so that every line longer than N characters (usually N=80 in a terminal) gets shorten to N characters maximum?

Answer 1

You can use cut to achieve this (using N=80 here):

some-command | cut -c -80

or

cut -c -80 some-file.txt

Replace 80 with the number of characters you want to keep.

Note that:

• Multi-bytes characters may not be handled correctly, depending on your implementation;
• Multi-characters bytes (aka tabs) may be treated as one char (& this question treats this).

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Dale Anderson suggests the use of some-command | cut -c -$COLUMNS which truncates to the current terminal width.

Libin Wen suggests that the equivalent cut -c 1-80 may be better for understanding.