Add prefix and suffix to every line in a .txt file

Simple sed approach:

sed 's/^/I am a /; s/$/ 128... [}/' file.txt

• ^ - stands for start of the string/line
• $ - stands for end of the string/line

The output:

I am a fruit, like 128... [}
I am a bike, like 128... [}
I am a dino, like 128... [}

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Alternatively, with Awk you could do:

awk '{ print "I am a", $0, "128... [}" }' file.txt

sed 's/.*/PREFIX&SUFFIX/' infile

will do, assuming PREFIX and SUFFIX don't contain any special characters.

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\&/ (backslash, ampersand and delimiter) are special when in the right hand side of a substitution. The special meaning of those characters can be suppressed by escaping them (preceding them by a backslash) e.g. to prepend A//BC and to append XY\Z&& one would run:

sed 's/.*/A\/\/BC&XY\\Z\&\&/' infile

Perl:

$ perl -lne 'print "I am a $_ 128... [}"' file 
I am a fruit, like 128... [}
I am a bike, like 128... [}
I am a dino, like 128... [}

More Perl:

$ perl -pe 's/^/I am a /; s/$/ 128... [}/' file 
I am a fruit, like 128... [}
I am a bike, like 128... [}
I am a dino, like 128... [}

And a bit more Perl:

$ perl -lpe '$_="I am a $_ 128... [}"' file 
I am a fruit, like 128... [}
I am a bike, like 128... [}
I am a dino, like 128... [}

For all of these, you can use -i to make the change in the original file:

$ perl -i -lne 'print "I am a $_ 128... [}"' file 
$ perl -i -pe 's/^/I am a /; s/$/ 128... [}/' file 
$ perl -i -lpe '$_="I am a $_ 128... [}"' file