add text in the middle of file

Shell Programming and Scripting
1

Can anyone help me pls? I want to add a text into the middle of file.
I've writtenthe following script

text to add="$1"
file="$2"
lines=$(wc -l $2)
half_lines=$(expr $lines / 2)
head -$half_lines $2 > temp
echo "text to add" >> temp
((half_lines=$half_lines + 1))
tail -$half_lines $2 >> temp
mv temp $2

it gives me `expr : syntax error

Can someone tell me what i did wrong. Was i not to use expr command?

2

Try the wc command manually, it gives the number of lines and as second field the filename.
That's why you get an error with the expr command.

Regards

3

Try this script

[[ -z $1 ]]&& echo "Argument needed "&& exit
[[ ! -s $1 ]]&& echo "File not found "&& exit
rm -f $1New
var=`wc -l <$1`
echo "Enter line no :\c"
read lineno
echo "Enter Text:\c"
read text
head -$lineno $1 >$1New
echo "$text" >>$1New
var1=$((var-lineno))
tail -$var1 $1 >>$1New

4

Hi Franklin
I have tried this but then i get an error command not found in line 5

5

Do you react on my response or on sanjaypraj reponse?

Regards

6

input:

first
second
forth
fifth

output:

first
second
third
forth
fifth

line=`cat a | wc -l`
half=`expr $line / 2`
nawk -v s="$half" '{
if(NR<=s) 
print
}' a
echo "third"
nawk -v s="$half" '{
if(NR>s) 
print
}' filename
7

How abt this

$cat test
first
second
fourth
fifth

$cat  test | awk '{print $0}(NR==2){print "third"}'
first
second
third
fourth
fifth