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Prepend a text to a file.

Terminal - Prepend a text to a file.
echo "text to prepend" | cat - file
2013-12-18 15:54:17
User: leni536
Functions: cat echo
1
Prepend a text to a file.

Prepend text to a file. It doen't need temporary files, ed or sed.

Alternatives

There are 15 alternatives - vote for the best!

Terminal - Alternatives
echo "text to prepend" | cat - file
sed -i '1s/^/text to prepend\n/' file1
2011-06-25 12:02:11
User: xeor
Functions: sed
Tags: sed replace
4

Using the sed -i (inline), you can replace the beginning of the first line of a file without redirecting the output to a temporary location.

prepend () { array=("$@"); len=${#array[@]}; file=${array[$len-1]}; text=${array[@]:0:$len-1}; printf '%s\n' 0a "$text" . w | ed -s "$file"; }
2013-12-09 21:59:26
User: zlemini
Functions: ed printf
Tags: sed replace
3

Syntax:

$ prepend content to add [filename]

Uses ed, so no temp files created.

sed -i 's/^/ls -l /' output_files.txt
2013-10-07 15:12:53
User: sonic
Functions: sed
Tags: sed replace
1

The original command is great, but I often want to prepend to every line.

Know a better way?

If you can do better, submit your command here.

What others think

This does not prepend to the file. It only prints it out before printing out the file. The original file is unchanged. It's no better than running this:

echo "text to prepend";cat file
Comment by tlemerond 51 weeks and 2 days ago

If you want to use the original and actually modify the file:

echo "text to prepend" | cat - file > file
Comment by tlemerond 51 weeks and 2 days ago

My bad, you can't use the same input and output file with cat. Best to use sed with the -i option.

Comment by tlemerond 51 weeks and 2 days ago

Your point of view

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