Inserting lines into a file through shell scripting

false-hopes · 04-30-2004, 04:47 PM

I'm not sure if this is the right place to ask, but I don't know where else is either. Does anyone know any way I can through shell scripting, insert lines into a file at a specified point, either after a certain number of bytes/kilobytes or a certain number of lines, the lines would be the best.

archtoad6 · 10-22-2005, 11:39 AM

My apologies for the pun ...

Here's a code fragment that may help:

Code:

# define source file
OLD=<source file>

# define insert file
TXT=<insert file>

# define result file
NEW=<result file>

# set insert point
N=<insert point>


# calculate file length
L=`wc -l $OLD  | awk '{print $1}'`

# calculate remaining file length
(( M = $L - $N + 1))

# assemble the new file
head -$N $OLD  > $NEW
cat      $TXT >> $NEW
tail -$M $OLD >> $NEW

There are other ways to get/define the inserted text, amongst them:

"here" doc embedded in the script
reading the text from the command line
reading a file name from the command line