Script Help

[Patrick Murphy]

I have a file with contains many lines with the work RESTART separated by other stuff. It is like this:

stuff
RESTART 0
stuff
stuff
RESTART 0
stuff
stuff
RESTART 0
stuff


In need to locate the last RESTART in the file and change the zero that follows it to a 2. All other lines with RESTART should remain unchanged. Please no Perl solutions.

Can someone help?

[Jonathan Fife]

Quick n dirty:

lastline=$(grep -n RESTART filename| tail -1 | cut -d: -f1)
awk -vll=$lastline '{if (NR==ll) print "RESTART 2"; else print $0}' filename

[Zinky]

Here's a plain and simple solution using "ed" - the standard UNIX editor:

Put in a script:

ed - file <

[Sandman!]

Here's a way to do it with ex(1):

# ex -s +"$(sed -n '/RESTART/=' infile)s/0/2/p | x" infile

~cheers

[Hein van den Heuvel]

It's tempting to make tow passes through the file, like Jonathan shows. AWK could do that readily.

If it is not too much data (less than 10MB?) then why not suck it into an array, and remember the element with the last 'RESTART'. At end fix that element and print all:


awk 'END {l[r]="RESTART 2"; while (i++ < NR) { print l[i]}} {l[NR]=$0} /^RESTART 0/{ r=NR}' old.txt > new.txt

Good luck,
Hein.

[Zinky]

ed - file <

[Patrick Murphy]

Thanks Jonathan it worked great.

[Patrick Murphy]

Jonathan's work the best for my situation. Thanks all for your help.