[sed] replace the first line with certain info

 

If you want to use sed to replace the first line of a file with

<div id="lexicoEntryPage">

then the proper command is:

sed '1s/.*/<div id="lexicoEntryPage">/' inputfile > outputfile

Explanation:

• 1 → applies the substitution only to line 1

• s → means substitute

• .* → matches the entire contents of the line

• The replacement text is <div id="lexicoEntryPage">

• The redirection > outputfile saves the modified result to a new file

If you want to edit the file in place (i.e., overwrite it):

sed -i '1s/.*/<div id="lexicoEntryPage">/' inputfile

⚠️ On macOS, sed -i requires an empty string argument to avoid backup creation:

sed -i '' '1s/.*/<div id="lexicoEntryPage">/' inputfile

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Would you like the command to also ensure a matching closing </div> tag at the end of the file (if not already present)?