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Buffer in order to avoir mistakes with redirections that empty your files

Terminal - Buffer in order to avoir mistakes with redirections that empty your files
buffer () { tty -s && return; tmp=$(mktemp); cat > "${tmp}"; if [ -n "$1" ] && ( ( [ -f "$1" ] && [ -w "$1" ] ) || ( ! [ -a "$1" ] && [ -w "$(dirname "$1")" ] ) ); then mv -f "${tmp}" "$1"; else echo "Can't write in \"$1\""; rm -f "${tmp}"; fi }
2009-07-27 20:21:15
User: Josay
Functions: cat echo mv rm tty
2
Buffer in order to avoir mistakes with redirections that empty your files

A common mistake in Bash is to write command-line where there's command a reading a file and whose result is redirected to that file.

It can be easily avoided because of :

1) warnings "-bash: file.txt: cannot overwrite existing file"

2) options (often "-i") that let the command directly modify the file

but I like to have that small function that does the trick by waiting for the first command to end before trying to write into the file.

Lots of things could probably done in a better way, if you know one...

Alternatives

There are 4 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

holy !@#$

Comment by linuxrawkstar 260 weeks and 4 days ago

debian/ubuntu moreutils has "sponge" which does what I think you're getting at:

sed '...' file | grep '...' | sponge file
Comment by eichin 260 weeks and 4 days ago

Perl can do that fine too, if we just want to use a replacement:

echo "zbc" > file.txt perl -pi -e 's/z/a/g' file.txt cat text.txt

abc

Comment by Blackbit 260 weeks and 2 days ago

Your point of view

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