R – PSake extensions

The easiest way is to use sed (or perl):

sed -i -e 's/abc/XYZ/g' /tmp/file.txt

Which will invoke sed to do an in-place edit due to the -i option. This can be called from bash.

If you really really want to use just bash, then the following can work:

while read a; do
    echo ${a//abc/XYZ}
done < /tmp/file.txt > /tmp/file.txt.t
mv /tmp/file.txt{.t,}

This loops over each line, doing a substitution, and writing to a temporary file (don't want to clobber the input). The move at the end just moves temporary to the original name.

For Mac users:

sed -i '' 's/abc/XYZ/g' /tmp/file.txt (See the comment below why)

You should be able to do this with

powershell -Command "& {Import-Module .\psake.psm1; Invoke-psake .\BuildTasks.ps1 %*}"

which gets rid of the build.ps1 file.