Output of sed in linux won't write to file

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Sed command find and replace in file and overwrite file doesnt work, it empties the file!

Ok so I've got this:

sed "s/^/getHtmlBody\(\"\/NmConsole\/Reports\/Workspace\/Virtualization\/WrVMwareHostList\/WrVMwareHostList.asp\?sGroupList=1'/g" out.bat | sed "s/$/\';--\");/g" >out.bat

And as you can see I'm trying to out into out.bat but it isn't working for some reason - nothing gets displayed on the screen but nothing is written to the file.

What am I doing wrong?

reading from out.dat and writing back into it at the same time? — iruvar, Jul 23 '12 at 02:27
This is a [famous pitfall](http://mywiki.wooledge.org/BashPitfalls#cat_file_.7C_sed_s.2BAC8-foo.2BAC8-bar.2BAC8_.3E_file) — kojiro, Jul 23 '12 at 02:30
Figures, ha. Works now after making the changes mentioned :) — Matthew 'mandatory' Bryant, Jul 23 '12 at 02:33

drevicko · Accepted Answer · 2017-12-01T11:59:26.687

2

When Bash sees "> out.bat" it truncates the file. The file is now empty, so sed doesn't find the beginnings nor ends of any lines and nothing gets put into out.bat

kojiro's link and an SO asnwer by codaddict has a nice description plus ways to get around it.

edited Dec 01 '17 at 11:59

answered Jul 23 '12 at 02:30

drevicko

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Output of sed in linux won't write to file

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