Shell Programming and Scripting

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I need a code in Ksh to search and replace a string in a file.

File A
---
AAAA A
BBBB B
CCCC C
DDDD E
FFFF F


File B:
--------
AAAA
BBBB
CCCC
DDDD


After running the script. I need the File B to be in following format

A
B
C
D

I use grep command to get corresponding value from file A

Then I tried to replace those values in file B

echo "s/$value1/$value2/\nwq!" | ex -s $FileB

I used a while loop and converted one by one.

But I got the following result

File B:

AAAA
BBBB
CCCC
D

Please help to solve this situation.

Thanks in advance

Deepak

You can do something like that:

Code:

awk '
   NR==FNR { rep[$1] = $ 2; next; }
   { if ($1 in rep) $1 = rep[$1]; print; }
    ' fileA fileB > fileB.tmp
mv fileB.tmp fileB

Jean-Pierre.

Xavier,
See if this works for you:

Code:

sed -e 's;^;s/;' -e 's; ;/;' -e 's;$;/;' file_A > $$sedTemp
sed -f $$sedTemp file_B
rm -f $$sedTemp

Hi,

I had a similar requirement sometime back. Check up the 'join' command in UNIX. The idea is to join (join as in a table-join in relational databases) the files using the first column and extracting the last column of the second file. Unfortunately, I dont have a UNIx box right now, and cant give you a concrete example.


Thanks,
Abhishek Ghose

Code:

join -1 1 -2 1 -o 1.2 filea fileb

Wont this work

Code:

join -o 1.2 filea fileb

There are two limitations with join :

Code:

$ cat fileA
AAAA A
BBBB B
CCCC C
DDDD E
FFFF F
$ cat fileB
BBBB
UUUU
CCCC
AAAA
DDDD
$ join -1 1 -2 1 -o 1.2 fileA fileB
B
$ join -o 1.2 fileA fileB         
B
$

Jean-Pierre.