truncate

shrink or extend the size of a file to the specified size

TLDR

Set a size of 10 GB to an existing file, or create a new file with the specified size

$ truncate --size [10G] [filename]
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Extend the file size by 50 MiB, fill with holes (which reads as zero bytes)

$ truncate --size +[50M] [filename]
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Shrink the file by 2 GiB, by removing data from the end of file

$ truncate --size -[2G] [filename]
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Empty the file's content

$ truncate --size 0 [filename]
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Empty the file's content, but do not create the file if it does not exist

$ truncate --no-create --size 0 [filename]
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SYNOPSIS

truncate OPTION... FILE...

DESCRIPTION

Shrink or extend the size of each FILE to the specified size

A FILE argument that does not exist is created.

If a FILE is larger than the specified size, the extra data is lost. If a FILE is shorter, it is extended and the sparse extended part (hole) reads as zero bytes.

Mandatory arguments to long options are mandatory for short options too.

-c, --no-create

do not create any files

-o, --io-blocks

treat SIZE as number of IO blocks instead of bytes

-r, --reference=RFILE

base size on RFILE

-s, --size=SIZE

set or adjust the file size by SIZE bytes

--help

display this help and exit

--version

output version information and exit

The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

SIZE may also be prefixed by one of the following modifying characters: '+' extend by, '-' reduce by, '<' at most, '>' at least, '/' round down to multiple of, '%' round up to multiple of.

REPORTING BUGS

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT

Copyright © 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

dd(1), truncate(2), ftruncate(2) Full documentation <https://www.gnu.org/software/coreutils/truncate> or available locally via: info '(coreutils) truncate invocation'

AUTHOR

Written by Padraig Brady.

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