BASH add in line

Question

hi

i want write code to add in line for ex open inittab file and add

c2:1235:respawn:/sbin/agetty 38400 tty2 linux
c3:1235:respawn:/sbin/agetty 38400 tty3 linux
c4:1235:respawn:/sbin/agetty 38400 tty4 linux
c5:1235:respawn:/sbin/agetty 38400 tty5 linux
c6:12345:respawn:/sbin/agetty 38400 tty6 linux
<<~~~ i want add code here 

# Local serial lines:
#s1:12345:respawn:/sbin/agetty -L ttyS0 9600 vt100
#s2:12345:respawn:/sbin/agetty -L ttyS1 9600 vt100

is there any way to do this in bash ?

Answer 1

Modify your inittab, then "init -q" to reload it. If your question is about file editing in bash, you can read a file and rewrite it in a loop like this :

for i in `cat thefile`
do
   echo $i >> someOtherFile
   if [ "some condition" == "some condition" ];
       then
       # do something else
   fi
done

This will read "thefile" line by line and write to "someOtherFile" while allowing you to insert whatever test to add lines in the flow.

Answer 2

one way

# awk '/^# Local serial lines/{ print "I wanna add code here\n"}1' /etc/inittab > temp
# mv temp /etc/inittab

then do init -q as wazoox says.

the other way: edit your inittab manually if its one time only.

Answer 3

Here is an alternative to wazoox script using an embedded awk snippet (I have added the init -q from wazoox)

#!/bin/bash

my_file=/etc/inittab
my_pattern="c6:12345:respawn:.* 38400 tty6 linux"

awk -f - ${my_file}<<__END__
{ print }
/${my_pattern}/ { 
    print "any code you want to add" 
}
__END__

init -q

Just check the pattern you want to detect and use "man awk" for the use of print. If you have a big code chunk to add you can use $(cat ${my_code_file}) in the awk snippet.