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Trouble with passing Variable from bash to awk gsub command

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# 8  
Old 12-09-2011
Quote:
Originally Posted by ni2
gsub does a global substitution. So try sub?

Code:
#!/bin/bash

echo "Enter Username"
read Username
echo "Field"
read FieldNo

awk -F: -v var=${Username} -v var2=${FieldNo} '$0 ~ var {sub($var2,"bar"); print}' FILENAME

Output
Code:
bar

does it work your end?

once again it works in my TEST directory, but not the real thing. Checked all variables this time...
# 9  
Old 12-09-2011
Using
Code:
#!/bin/bash

echo "Enter Username"
read Username
echo "Field"
read FieldNo

awk -F: -v var=${Username} -v var2=${FieldNo} '$0 ~ var {sub($var2,"bar"); print}' FILENAME

Code:
$bash test.sh
Enter Username
Carl
Field
3
Carl foo bar

Code:
$less FILENAME
Richard:foo:foo
Sam:foo:foo
Carl:foo:foo

Moving on to your other request. What you posted should also work. But it would replace *all* occurrances of data with newdata in that record. Using sub will replace the first occurance of that data with newdata in that record.
Code:
read data
read newdata

awk -F: -v var=${Username} -v var1=${data} -v var2=${newdata} '$0 ~ var {gsub(var1,var2); print}' FILENAME

# 10  
Old 12-09-2011
Quote:
Originally Posted by Nostyx
Thanks for the help but that doesn't produce any output for me.
Double check, my suggestion definitely works. This script:
Code:
#!/bin/bash

cat >FILENAME <<%
Quote:
Richard:foo
Sam:foo
Carl:foo
Bug:foo Richard
%

set -x
Username=Richard
awk -F: '/^'"$Username"':/ {gsub(/foo/,"bar", $2); print}' FILENAME

awk -F: -v var=${Username} '$0 ~ var {gsub(/foo/,"bar",$2); print}'  FILENAME

produces this output:
Code:
+ Username=Richard
+ awk -F: '/^Richard:/ {gsub(/foo/,"bar", $2); print}' FILENAME
Richard bar
+ awk -F: -v var=Richard '$0 ~ var {gsub(/foo/,"bar",$2); print}' FILENAME
Richard bar
Bug bar Richard

There is extra line which doesn't match the requirement with the second awk oneliner.
Quote:
do you not have to -v and assign the shell variable as an awk variable before using it with an awk command?
You have to indeed. My point is you might just don't need an awk variable in the first place, especially if you use it only once.
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