UNIX for Beginners Questions & Answers

If the \. is within the ( ) then the \1 puts it back in.

Code:

sed -r 's/(.*\.)[0-9]{1,2}/\1'"$val"'/' file

The -r is ERE in GNU sed. A Unix sed needs the standard RE or BRE:

Code:

sed 's/\(.*\.\)[0-9]\{1,2\}/\1'"$val"'/' file

Thanks!
Slight modification to the original problem:

So previously I wanted to replace the last digit before the single quote at end of line with a new value, but now I want to only do it based on the previous digits and a matching pattern.

If any(part of) line in file matches a certain pattern, replace the value after the last dot (and keep the single quote at end of line-same as before) with the value in pattern.
Can I do this using sed?


example:
Pattern to match=name1:1.2.300.Y (or could be name1:1.300.Y, so Y can be any number, I don't care what it is at this point).

All lines will be in the same format and ideally there will only be one line containing 'name1'.

Pattern to match= name1:1.2.300.Y

Original file:

Code:

person1_desc: 'info:200/text/name1:1.2.300.X'
person1_desc: 'info:200/text/name1:1.2.400.A'
person1_desc: 'info:200/text/name1:5.6.700.B'
person2_desc: 'info:200/text/name2:1.2.300.C'

Output file:

Code:

person1_desc: 'info:200/text/name1:1.2.300.Y'
person1_desc: 'info:200/text/name1:1.2.400.A'
person1_desc: 'info:200/text/name1:5.6.700.B'
person2_desc: 'info:200/text/name2:1.2.300.C'

So only the first line was a match and updated, 'X' was replaced with 'Y'. Line 4 wasn't changed( name2)



Pattern I'm looking for:

Code:

name1:1.2.300.Y

In other words:
{string}:{ a combination of one or more numbers and dots, not always 2 dots, but grouped together}.{one or more digits}

Or if I could also extract each field above from the original file into variables:

Code:

Var1=name1
Var2=1.2.300
Var3=Y

If it helps, my pattern-to-look-for could also be:

Code:

info:200/text/name1:1.2.300.Y

Instead of just:

Code:

name1:1.2.300.Y

I hope I explained it well, sorry if I might have over done it!
Thanks!!

---------- Post updated at 10:49 PM ---------- Previous update was at 10:48 PM ----------


Yes that works, thank you!
Slight modification to original problem:


previously I wanted to replace the last digit before the single quote at end of line with a new value, but now I want to only do it based on the previous digits and a matching pattern.

If any(part of) line in file matches a certain pattern, replace the value after the last dot (and keep the single quote at end of line-same as before) with the value in pattern.
Can I do this using sed?


example:
Pattern to match= name1:1.2.300.Y (or could be name1:1.300.Y, so Y can be any number, I don't care what it is at this point).

All lines will be in the same format and ideally there will only be one line containing 'name1'.

Pattern to match= name1:1.2.300.Y

Original file:

Code:

person1_desc: 'info:200/text/name1:1.2.300.X'
person1_desc: 'info:200/text/name1:1.2.400.A'
person1_desc: 'info:200/text/name1:5.6.700.B'
person2_desc: 'info:200/text/name2:1.2.300.C'

Output file:

Code:

person1_desc: 'info:200/text/name1:1.2.300.Y'
person1_desc: 'info:200/text/name1:1.2.400.A'
person1_desc: 'info:200/text/name1:5.6.700.B'
person2_desc: 'info:200/text/name2:1.2.300.C'

So only the first line was a match and updated, 'X' was replaced with 'Y'. Line 4 wasn't changed( name2)



Pattern I'm looking for:

Code:

name1:1.2.300.Y

In other words:
{string}:{ a combination of one or more numbers and dots, not always 2 dots, but grouped together}.{one or more digits}

Or if I could also extract each field above from the original file into variables:

Code:

Var1=name1
Var2=1.2.300
Var3=Y

If it helps, my pattern-to-look-for could also be:

Code:

info:200/text/name1:1.2.300.Y

Instead of just:

Code:

name1:1.2.300.Y

I hope I explained it well, sorry if I might have over done it!
Thanks!!

Moderator's Comments:

Please use CODE tags as required by forum rules!

PLEASE exercise some care when editing a post NOT to duplicate its contents!

You best have two strings, one is the search pattern and one is the replacement value.

Code:

#!/bin/sh
pattern=$1
newval=$2
if [ $# -ne 2 ]; then
  echo "usage: $0 'RE pattern' newval"
  exit 1
fi
sed 's/\(.*'"$pattern"'\.\)[0-9]\{1,\}/\1'"$newval"'/' file

Here the given pattern must reach to the last . (before the last number). For example you can run your script with
./scriptname 'name1:1\.2\.300' 199 or ./scriptname ':1\.2\.300' 199 but not ./scriptname 'name1:1\.2\.' 199.
The following modification searches the pattern in the whole line:

Code:

sed '/'"$pattern"'/ s/\(.*\.\)[0-9]\{1,\}/\1'"$newval"'/' file

This requires you to end the given pattern with a \. (otherwise there is a risk you match the first part of the number).
As an alternative you can put the trailing \. into the sed code

Code:

sed '/'"$pattern"\.'/ s/\(.*\.\)[0-9]\{1,\}/\1'"$newval"'/' file

and you must *not* give the trailing \..

Hi,

Can you please try and adapt if your input/output changes ?

Code:

cat file
person1_desc: 'info:200/text/name1:1.2.300.X'
person1_desc: 'info:200/text/name1:1.2.400.A'
person1_desc: 'info:200/text/name1:5.6.700.B'
person2_desc: 'info:200/text/name2:1.2.300.C'
person2_desc: 'info:200/text/name1:1.298.X'

Code:

sed -re 's/([a-z]+1:[0-9].[0-9]?.?[0-9]{3}.)(X)/\1Y/' file

Thanks ,
Could you please explain how the sed is working? so I can understand how to make slight modificiations

Also, my input will actually be the whole line:

Code:

info:200/text/name1:1.2.300.Y

So based on that I need to do:

1.get pattern

Code:

pattern=info:200/text/name1:1.2.300

2.escape the / in the pattern (right?)

Code:

pattern=info:200\/text\/name1:1.2.300

3.put pattern in single quptes

Code:

pattern='info:200\/text\/name1:1.2.300'

4.get newval

Code:

newval=Y

and then call the sed
how can I extract all those values?


Thanks again!

Hi,
Did you try the code posted in my previous post ?

"how can I extract all those values"
What do you mean by that ?
Please provide input & expected output.