command to write on first line of a file (as a heading for columns) in linux/solaris.

Sha_unix · 11-22-2011, 01:32 PM

Hi,

i have file which is few line. i want to add some heading to the file in the first line. How can i?

TB0ne · 11-22-2011, 01:39 PM

Quote:

Originally Posted by Sha_unix

Hi,
i have file which is few line. i want to add some heading to the file in the first line. How can i?

You write a script to do it.

Echo your header to the file, then use the cat with the append operator ">>" to put the rest of the text into it, then use the mv (or cp) command(s) to get the file named what you want, and try to reference the man pages and Google scripting examples first.

Something like this:

Code:

echo "my header" > file1.txt
cat file-contents.txt >> file1.txt
mv file1.txt file-contents.txt

or use sed with inline-editing:

Code:

sed -i '1imy new header text is this' file-contents.txt

Sha_unix · 11-22-2011, 01:52 PM

Hmmm k i can try that, but file looks like below. So if i have to seperate "," (comma) with space or tab. how can i do it.

quote:
"Newcomm_data",45,10486266,10148863
"Newcomm_index",46,3145741,1943543
"comm_data",47,8646650,7228927
"comm_index",48,2097166,1786591
"RUNLOG_Data_01",55,1311230,210943
[/quote]

i want to give heading like this

quote:
AreaName AreaNo TotalBlocks HiWaterMark
[/quote]

TB0ne · 11-22-2011, 02:09 PM

Quote:

Originally Posted by Sha_unix

Hmmm k i can try that, but file looks like below. So if i have to seperate "," (comma) with space or tab. how can i do it.

Code:

"Newcomm_data",45,10486266,10148863
"Newcomm_index",46,3145741,1943543
"comm_data",47,8646650,7228927
"comm_index",48,2097166,1786591
"RUNLOG_Data_01",55,1311230,210943

i want to give heading like this

Code:

AreaName AreaNo TotalBlocks HiWaterMark

You were given the solution...how about trying it, and then trying to figure out how to make it work for your exact needs?? Read man pages...try Google. Coming back with each command, saying "it's not working!!!", shows little effort on your part, when you've been given the solution already.

Your request was for how to put a header into a file. I gave you two solutions that work. Want spaces in it? Put them in...and here's a hint: read your previous threads about replacing things, then think about what you did to get characters substituted. That was a backslash, right?? Think that would work here????

Karl Godt · 11-22-2011, 04:46 PM

Code:

#!/bin/sh

AreaName="$LANG"
AreaNo="`rdev | cut -f 1 -d ' '`"
TotalBlocks="`fdisk -l | grep "^$AreaNo" | tr -s ' ' | cut -f 4 -d ' '`"
HiWaterMark="$((TotalBlocks/100*90))"

echo "\"Newcomm_data\",45,10486266,10148863
\"Newcomm_index\",46,3145741,1943543
\"comm_data\",47,8646650,7228927
\"comm_index\",48,2097166,1786591
\"RUNLOG_Data_01\",55,1311230,210943
" > /tmp/test.txt

HEADER="#**************
#
# $AreaName $AreaNo $TotalBlocks $HiWaterMark
#
#*********************"

echo "$HEADER"
echo

sed -i "$HEADER" /tmp/test.txt

cat /tmp/test.txt

corp769 · 11-22-2011, 05:07 PM

Quote:

Originally Posted by Karl Godt

Code:

#!/bin/sh

AreaName="$LANG"
AreaNo="`rdev | cut -f 1 -d ' '`"
TotalBlocks="`fdisk -l | grep "^$AreaNo" | tr -s ' ' | cut -f 4 -d ' '`"
HiWaterMark="$((TotalBlocks/100*90))"

echo "\"Newcomm_data\",45,10486266,10148863
\"Newcomm_index\",46,3145741,1943543
\"comm_data\",47,8646650,7228927
\"comm_index\",48,2097166,1786591
\"RUNLOG_Data_01\",55,1311230,210943
" > /tmp/test.txt

HEADER="#**************
#
# $AreaName $AreaNo $TotalBlocks $HiWaterMark
#
#*********************"

echo "$HEADER"
echo

sed -i "$HEADER" /tmp/test.txt

cat /tmp/test.txt

You do know that providing the full answer, without explaining what everything does, will not help the OP learn how to do it on his/her own, right?

David the H. · 11-23-2011, 08:50 AM

90. How do I prepend a text to a file (the opposite of >>)?

http://mywiki.wooledge.org/BashFAQ/090

Basically, this is the kind of question that gets asked, and answered, all the time. You really should get into the habit of doing a few web and forum searches first.

corp769 · 11-23-2011, 09:07 AM

Quote:

Originally Posted by David the H.

90. How do I prepend a text to a file (the opposite of >>)?

http://mywiki.wooledge.org/BashFAQ/090

Basically, this is the kind of question that gets asked, and answered, all the time. You really should get into the habit of doing a few web and forum searches first.

Just your two cents? Or would that be more like a whole dollar?

jschiwal · 11-23-2011, 09:46 AM

Separating the fields with tabs, you will have columns that don't line up because some entries are too long, pushing the next column over to the next tab. You might want to look at using AWK with formatted printing, to control where each field should start.

Such as this:

Code:

AreaName           AreaNo TotalBlocks    HiWaterMark
----------------------------------------------------
"Newcomm_data"       45   10486266        10148863
"Newcomm_index"      46    3145741         1943543
"comm_data"          47    8646650         7228927
"comm_index"         48    2097166         1786591
"RUNLOG_Data_01"     55    1311230          210943

The header can be printed in the BEGIN clause. I produced this with a one line awk command.

Sha_unix · 11-23-2011, 02:14 PM

Thank you very much all