How to append a line at the beginning of a file

[M.Thomas]

Hi Admins,
In shell scripting, I want to append a line at the starting of file not at the ending
Please tell me how to do that

Thanks in advance
Thomas

[Geoff Wild]

Use sed

sed '1i\
your text goes here' file_name > new_filename

Rgds...Geoff

[Sandman!]

#!/usr/bin/sh

ex -s input_filename <<-EOF
0r !echo insert this at the top of input_filename
wq
EOF

[James R. Ferguson]

Hi Thomas:

# perl -pi.old -e 'print "NEWLINE" if $.==1' fiie

This will update "inplace" the file(s) passed while making a backup copy as "*.old".

Regards!

...JRF...

[A. Clay Stephenson]

#!/usr/bin/sh

typeset FNAME=/xxx/yyy/myfile
typeset TDIR=${TMPDIR:-/var/tmp}
type T1=${TDIR}/F${$}_1.tmp
typeset -i STAT
typeset PROG=${0##*/}

if [[ -r "${FNAME}" ]]
then
trap 'eval rm -f ${T1}' 0 1 2 3 15

echo "Here is my new stuff" > ${T1}
cat ${FNAME} >> ${T1}
STAT=${?}
if [[ ${STAT} -eq 0 ]]
then
mv ${T1} ${FNAME}
STAT=${?}
else
echo "${PROG}: Cat failed; status ${STAT}." >&2
fi
else
echo "${PROG}: Can't open \"${FNAME}\"; status ${STAT}." >&2
fi
exit ${STAT}

[James R. Ferguson]

Hi (again) Thomas:

If you want only "shell" you can achieve your goal on a commandline thusly:

# echo "NEWLINE"|cat -- - file

This will place "NEWLINE" *before* the "file" contents.

Notice that "--" signals the end of switches for 'cat' and the "-" signifies STDIN as input (along with the name of the file you want to follow it with.

Regards!

...JRF...

[Peter Nikitka · Accepted solution]

Hi,

as one liner:

print "Prepended to file" | cat - origfile >/tmp/tmpfile$$ && mv /tmp/tmpfile$$ origfile

mfG Peter

[M.Thomas]

Thanks to all for your quick response

Regards
Thomas

[Steve Post]

I know this is closed. I see the most obvious and simple solution was missing:

To add "my dog has fleas" to the top of file X.

cat "my dog has fleas" > X.tmp
cat X >> X.tmp
cat /dev/null > ./X
cat X.tmp >> ./X

Perhaps it was missed because it is inefficient and wipes the file for a portion of time. It requires more space because you have making a 2nd copy of file X.

Backwards writing it is.
You are appending the entire file X to the bottom of a one line file.