Truncate a file: Difference between revisions
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=={{header|jq}}==
jq cannot itself perform the specified task
because it cannot "truncate a file" in the sense of the question.
In particular, it is not "binary safe", and cannot itself write to files named on the command line.
Another issue is that jq can only read UTF-8-encoded files, and generally speaking is oriented
to codepoints rather than bytes.
So for this task, we'll assume that `sponge` is available for overwriting a file,
and that the "size" is specified in codepoints rather than bytes.
<pre>
< input.txt jq -Rr --argjson size $size '
if length < $size then "file size is less than the specified size" | error
else .[:$size]
end
' | sponge input.txt
</pre>
=={{header|Julia}}==
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