Empty a file in linux bash

Question

which one is the best way to clean or empty a file in Linux? I have to zip ( tar ) a file to an archive and then clean/empty it; this is what I do and it works correctly:

tar -zcvf /mnt/file.tar.gz /mnt/file.txt > /dev/null 2>&1

echo "" > /mnt/file.txt

I'm doing it with echo, probably there is a better way ?

Thanks

These many answers for a blatant duplicate? not a single vote to close? — Inian, Oct 30 '19 at 08:27

score 6 · Answer 1 · edited Oct 30 '19 at 13:51

6

There are multiple ways to do that:

We presume that our file is called access.log and it's in the current directory:

1.

: > access.log

2.

true > access.log

3.

cat /dev/null > access.log

4.

cp /dev/null access.log

5.

dd if=/dev/null of=access.log

6.

echo -n "" > access.log

7.

echo -n > access.log

edited Oct 30 '19 at 13:51

Wiimm

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answered Oct 30 '19 at 07:50

Dan Ionescu

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Solutions 6+7 don't empty the file, because they write a line feed. `echo -n` fix it. (I edit both). – Wiimm Oct 30 '19 at 13:12
@Wimm i've tested those and they work, the ">" operator overrides the file content with what's given, in our case an empty string – Dan Ionescu Oct 30 '19 at 13:20
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@Dan nah, echo prints a line feed without -n. try `echo > access.log && wc -c – oguz ismail Oct 30 '19 at 13:47

score 5 · Answer 2 · answered Oct 30 '19 at 07:49

5

Just truncate it:

truncate -s 0 file

answered Oct 30 '19 at 07:49

oguz ismail

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score 2 · Answer 3 · answered Oct 30 '19 at 07:48

2

one option is:

touch passbook.txt

Another option to make empty file in Linux is just type the following command:

> file-name-here
echo '' > filename
ls filename
file filename

answered Oct 30 '19 at 07:48

Danilo Mercado Oudalova

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RavinderSingh13 · Answer 4 · 2019-10-30T07:56:46.197

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EDIT(zipping file and nullifying actual file): Taking inspiration from @oguz ismail's fine answer, I am using truncate option with zip of the file too here.

tar -zcvf file.tar.gz file.txt && truncate -s 0 file.txt

I will go with > /mnt/file.txt a bit easier than echo.

edited Oct 30 '19 at 07:56

answered Oct 30 '19 at 07:48

RavinderSingh13

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score 0 · Answer 5 · answered Oct 30 '19 at 07:52

0

tar czvf /tmp/empty.tar.gz --files-from=/dev/null --overwrite

I found a way here

answered Oct 30 '19 at 07:52

wailinux

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IMHO I don't think OP is looking to create an empty zip file, he/she is looking for zipping a file and then nullifying actual file, if I got it correctly. – RavinderSingh13 Oct 30 '19 at 08:00

Empty a file in linux bash

5 Answers5