I have this ssh config that needs to be edited.
Host vps6
HostName 123.456.789.00
User dylan
Port 123
Host vps4
HostName 123.456.789.00
User dylan
Port 123
# old server
Host vps3-old
HostName 123.456.789.00
User dylan
Port 123
I want to move config for vps6 to end of file and append -old to its config alias. The resulting file would be.
Host vps4
HostName 123.456.789.00
User dylan
Port 123
# old server
Host vps3-old
HostName 123.456.789.00
User dylan
Port 123
Host vps6-old
HostName 123.456.789.00
User dylan
Port 123
I managed to do exactly that using this sed command → sed '/'"vps4"'/{N;N;N;N;H;$!d}; ${p;x;s/'"vps4"'/'"vps4"'-old/}', unfortunately this gives me unwanted newline at the end of file.
[tmp]$ sed '/'"vps6"'/{N;N;N;N;H;$!d}; ${p;x;s/'"vps6"'/'"vps6"'-old/}' config
Host vps4
HostName 123.456.789.00
User dylan
Port 123
# old server
Host vps3-old
HostName 123.456.789.00
User dylan
Port 123
Host vps6-old
HostName 123.456.789.00
User dylan
Port 123
[tmp]$ # See above me
Moreover, I want to be able to specify the next n line to be moved (for example above will be mark Host vps4 and next 3 line to be moved to end of file). I have searched up the net and found out that the recommended tools for this kind of task is ed, but I have yet to find out the example command to do exactly what I want.
With your shown samples please try following awk code.
awk '
!NF && found{
found=""
next
}
/^Host vps6/{
found=1
line=$0"-old"
next
}
found{
val=(val?val ORS:"")$0
next
}
!found
END{
print ORS line ORS val
}
' Input_file
NOTE: In case you want to save output into Input_file itself then run above program it will print output on terminal and once you are Happy with results of above program then you can append > temp && mv temp Input_file to above program, to do inplace save into Input_file.
Explanation: Adding detailed explanation for above used code.
awk ' ##Starting awk program from here.
!NF && found{ ##Checking if line is empty AND found is SET then do following.
found="" ##Nullifying found here.
next ##next will skip all further statements from here.
}
/^Host vps6/{ ##If line starts from Host vps6 then do following.
found=1 ##Setting found here.
line=$0"-old"
next
}
found{ ##If found is set then do following.
val=(val?val ORS:"") $0 ##Creating val which is keep adding current line into it.
next ##next will skip all further statements from here.
}
!found ##If found is NOT set then print that line.
END{ ##Starting END block of this program from here.
print ORS line ORS val ##Printing ORS line ORS and val here.
}
' Input_file ##Mentioning Input_file name here.