Sed & Mac OS Terminal: How to remove parentheses content from the first line of every file? - macos

Question

I am on Mac Os 10.14.6 and have a directory that contains subdirectories that all contain text files. Altogether, there are many hundreds of text files.
I would like to go through the text files and check for any content in the first line that is in parentheses. If such content is found, then the parentheses (and content in the parentheses) should be removed.
Example:
Before removal:
The new world (82 edition)
After removal:
The new world
How would I do this?
Steps I have tried:
Google around, it seems SED would be best for this.
I have found this thread, which provides SED code for removing bracketed content.
sed -e 's/([^()]*)//g'
However, I am not sure how to adapt it to work on multiple files and also to limit it to the first line of those files. I found this thread which explains how to use SED on multiple files, but I am not sure how to adapt the example to work with parentheses content.
Please note: As long as the solution works on Mac OS terminal, then it does not need to use SED. However, from Googling, SED seems to be the most suited.

Answer 1

I managed to achieve what you're after simply by using a bash script and sed together, as so:
#!/bin/bash
for filename in $PWD/*.txt; do
sed -i '' '1 s/([^()]*)//g' $filename
done
The script simply iterates over all the .txt files in $PWD (the current working directory, so that you can add this script to your bin and run it anywhere), and then runs the command
sed -ie '1 s/([^()]*)//g' $filename
on the file. By starting the command with the number 1 we tell sed to only work on the first line of the file :)
Edit: Best Answer
The above works fine in a directory where all contained objects are files, and not including directories; in other words, the above does not perform recursive search through directories.
Therefore, after some research, this command should perform exactly what the question asks:
find . -name "*.txt" -exec sed -i '' '1 s/([^()]*)//g' {} \;
I must iterate, and reiterate, that you test this on a backup first to test it works. Otherwise, use the same command as above but change the '' in order to control the creation of backups. For example,
find . -name "*.txt" -exec sed -i '.bkp' '1 s/([^()]*)//g' {} \;
This command will perform the sed replace in the original file (keeping the filename) but will create a backup file for each with the appended .bkp, for example test1.txt becomes test1.txt.bkp. This a safer option, but choose what works best for you :)

Answer 2

Good try,
The command you where looking for single line:
sed -E '1s|\([^\)]+\)||'
The command to replace each input file first line:
sed -Ei '1s|\([^\)]+\)||' *.txt
example:
echo "The new world (82 edition)" |sed -E '1s|\([^\)]+\)||'
The new world
Explanation
sed -Ei E option: the extended RegExp syntax, i option: for in-place file replacement
sed -Ei '1s|match RegExp||' for first line only, replace first matched RegExp string with empty string
\([^\)]+\) RegExp matching: start with (, [^\)]any char not ), + - more than once, terminate with )

Answer 3

Try:
# create a temporary file
tmp=$(mktemp)
# for each something in _the current directory_
for i in *; do
# if it is not a file, don't parse it
if [ ! -f "$i" ]; then continue; fi
# remove parenthesis on first line, save the output in temporary file
sed '1s/([^)]*)//g' "$i" > "$tmp"
# move temporary file to the original file
mv "$tmp" "$i"
done
# remove temporary file
rm "$tmp"