Bash script to edit a bunch of files

Question

To process a bunch of data and get it ready to be inserted into our database, we generate a bunch of shell scripts. Each of them has about 15 lines, one for each table that the data is going. One a recent import batch, some of the import files failed going into one particular table. So, I have a bunch of shell scripts (about 600) where I need to comment out the first 7 lines, then rerun the file. There are about 6000 shell scripts in this folder, and nothing about a particular file can tell me if it needs the edit. I've got a list of which files that I pulled from the database output.

So how do I write a bash script (or anything else that would work better) to take this list of file names and for each of them, comment out the first 7 lines, and run the script?

EDIT:

#!/usr/bin/env sh

cmd1
cmd2
cmd3
cmd4
cmd5
cmd6
cmd7
cmd8

Not sure how readable that is. Basically, the first 7 lines (not counting the first line) need to have a # added to the beginning of them. Note: the files have been edited to make each line shorter and partially cut off copying out of VIM. But in the main part of each file, there is a line starting with echo, then a line starting with sqlldr

Answer 1

Using sed, you can specify a line number range in the file to be changed.

#!/bin/bash

while read line
do
    # add a comment to beginning of lines 1 - 7 and rename the script
    sed '3,9 s/^/#/' $line > $line.new
    exec $line.new
done < "filelist.txt"

You may wish to test this before running it on all of those scripts...

EDIT: changed the lines numbers to reflect comments.

Answer 2

Roughly speaking:

#!/bin/sh
for file in "$@"
do
    out=/tmp/$file.$$
    sed '2,8s/^/#/' < $file > $out
    $SHELL $out
    rm -f $out
done

Assuming you don't care about checking for race conditions etc.

Answer 3

ex seems made for what you want to do.

For instance, for editing one file, with a here document:

#!/bin/sh

ex test.txt << END
1,12s/^/#/
wq
END

That'll comment out the first 12 lines in "test.txt". For your example you could try "$FILE" or similar (including quotes!).

Then run them the usual way, i.e. ./"$FILE"

edit: $SHELL "$FILE" is probably a better approach to run them (from one of the above commenters).

Answer 4

Ultimately you're going to want to use the linux command sed. Whatever logic you need to place in the script, you know. But your script will ultimately call sed. http://lowfatlinux.com/linux-sed.html