Insert a word in the first line of the file

Question

Input:

firstline
secondline
thirdline

...some magic happens here... :)

Output:

insertedtextfirstline
secondline
thirdline

Question: How can I insert the insertedtext to the start of the first line in a file?

Solution 1

With GNU sed:

sed -i '1s/^/insertedtext/' file

This replaces the beginning of the first line with the inserted text. -i replaces the text in file rather than sending the modified text to the standard output.

Solution 2

If portability across unices is a concern, use ed:

ed file <<END
1s/^/insertedtext/
w
q
END

Solution 3

POSIX one:

$ { printf %s insertedtext; cat <./input_file; } >/tmp/output_file
$ mv -- /tmp/output_file ./input_file

Solution 4

In perl

perl -pi -e 's/^/insertedtext/ if $.==1' myfile.txt

Solution 5

Another variation - not more or less correct, just a matter of taste:

awk 'BEGIN{printf "insertedtext"};{print $0}' file1.txt > file2.txt

View more solutions

Comments

[Admin]

Do you have to enter only at the first line of the file, or this first line at different sections of the file, for example, paragraphs?

[John Pretak]

gorkypl has a point. If you have a large document with multiple first line situations, you might to invest in a proper code.

[dan]

This is the fastest method (compared to sed, ed or ex).

[lcd047]

+1 for the use of ed(1). :)

[cuonglm]

This one removed all trailing newlines of infile.

[mikeserv]

@cuonglm - good point.