awk search/replace specific field, using variables for regexp & subsitution then overwrite file
Hello,
I'm trying the solve the following problem.
I have a file which I intend to use as a csv called master.csv
The columns are separated by commas.
I want to change the text on a specific row in either column 3,4,5 or 6 from xxx to yyy depending upon if column 1 matches a specified pattern.
The column to change (i.e. 3/4/5/6) is dependent upon the value of the variable in a nested loop
The awk statement is located within a nested loop of a parent loop. It will use the variable value from the parent loop for column 1 and the variable value from the nested loop for column 3/4/5/6.
Below is an example of the code:
I know there are a few problems with my awk statement:
firstly, When passing the variables to awk nothing is produced by the print command.
I have tried the above on the command line using fixed values and I get the output I require:
However, this creates another problem as I want to edit the master csv file. I can't redirect the awk stdout to a temp file then move back because I'd lose all the other entries. The only workarounds I can see for this problem are:
a) using awk to print the entire list with the changes applied, then I can use temp file. I'm not sure this is even possible as it defys the point of using awk pattern matching to print specific columns/rows.
b) run sed -i within the awk command (i've been googling the syntax to this but can't find it).
Apologies that was long winded. If you want me to clarify anything please let me know.
In essence I want to know:
1) how to pass multiple variables to awk command and use them in an regular expression & subsitution
2) how to edit the master csv file
Any help/advice would be much appreciated
Hi,
I have been trying to use awk with variables that needs to search for a pattern and replace it with another pattern, the patterns are supplied in a variable. I have tried several different ways without success and hope that someone can help me. Here are the details
echo $UPC
07007457809... (2 Replies)
hi,
i am doing
awk '{gsub("hello", "bye", $0); print}' test.dat
but I want to actually store the results of this global change into the file test.dat itself, i.e. I don't want the results to come to stdout, I want the results to overwrite the initial file
how can I do this?
thanks (3 Replies)
I am writing a c++ program that has many calls of pow(input,2). I now realize that this is slowing down the program and these all should be input * input for greater speed.
There should be a simple way of doing this replacement throughout my file with awk, but I am not very familiar with awk.... (2 Replies)
I need to replace specific field (x) in a table with new value (y):
Input:
1 2 3 4
5 x 6 7
8 9 0 0
Output:
1 2 3 4
5 y 6 7
8 9 0 0
I have no idea how to do this. (10 Replies)
Hello everybody:
I want to replace any field $2 of any file line (f.i. test.txt) matching $1 with a shell variable.
$ cat test.txt
F 0
B A
H -12.33
Now I'm going to ask the value of variable B:
$ SEARCHVAR=B
$ OLDVAL=$(awk -v SEARCHVAR="$SEARCHVAR"... (4 Replies)
Hi!
I have a difficult problem, to step up a unknown version number in a text file, and save the file. It would be great to run script.sh and the version gets increased.
Example the content of the textfile.txt
hello
version = x
bye
This include three steps
1. First find the char after... (2 Replies)
I'm trying to update a text file via sed/awk, after a lot of searching I still can't find a code snippet that I can get to work.
Brief overview:
I have user input a line to a variable, I then find a specific value in this line 10th field in this case. After asking for new input and doing some... (14 Replies)
Hi
I would like to apply this gawk command:
gawk '{$0=gensub(/\y+\y/,"","g"); print}' file
not to the whole $0 but just to the part of $0 that is between:
(a number)"> and </mrk>
Is it possible?
thanks for your help. (4 Replies)
Hi,
I have a file like below
PRUM,67016800 ,CC ,C1,67016800 , ,Y,Y,2 ,CK,BX,FOX ,00000001,EA,00000001,20141120 00:00:00, ,N,Y,Y,CK ABCDEF... (7 Replies)
I have been reading old posts and trying to come up with a solution for the below: Use a tab-delimited input file to assign
point to variables that are used to update a specific field, Rank. I really couldn't find too much in the way of assigning points
to variable, but made an attempt at an awk... (4 Replies)
Discussion started by: cmccabe
4 Replies
LEARN ABOUT LINUX
igawk
IGAWK(1) Utility Commands IGAWK(1)NAME
igawk - gawk with include files
SYNOPSIS
igawk [ all gawk options ] -f program-file [ -- ] file ...
igawk [ all gawk options ] [ -- ] program-text file ...
DESCRIPTION
Igawk is a simple shell script that adds the ability to have ``include files'' to gawk(1).
AWK programs for igawk are the same as for gawk, except that, in addition, you may have lines like
@include getopt.awk
in your program to include the file getopt.awk from either the current directory or one of the other directories in the search path.
OPTIONS
See gawk(1) for a full description of the AWK language and the options that gawk supports.
EXAMPLES
cat << EOF > test.awk
@include getopt.awk
BEGIN {
while (getopt(ARGC, ARGV, "am:q") != -1)
...
}
EOF
igawk -f test.awk
SEE ALSO gawk(1)
Effective AWK Programming, Edition 1.0, published by the Free Software Foundation, 1995.
AUTHOR
Arnold Robbins (arnold@skeeve.com).
Free Software Foundation Nov 3 1999 IGAWK(1)