write in the same file of input

[m47730]

Hi,
i like your work to create a more modern envsubst combined with statically compiling with musl, it's a very portable and efficient solution.

I have a minor request: is it possible to implement write the output in the same file as input? (without using some other tool like sponge)

ex:

cat test.txt
test: it $TEST

export TEST=work
renvsubst --variable=TEST --input=test.txt --output=test.txt
file test.txt
  test.txt: empty

if the output file is different, it works perfectly:

renvsubst --variable=TEST --input=test.txt --output=test2.txt
cat test2.txt
test: it work

[gi8lino]

hi @m47730

I like your idea! I’ll try to add a flag for this.

In the meantime, you can use something like this:

cat test.txt
test: it $TEST

export TEST=work
cat test.txt | ./renvsubst | tee test.txt
file test.txt
  test.txt: test: it work

It is ugly, but working.

[m47730]

great to hear it!

I used your solution in the meantime, i ended up on something like:

# substitute variables in the same file of input
./renvsubst --variable TEST --input test.txt | tee test.txt 1>/dev/null

Thank you