UNIX for Dummies Questions & Answers

Maybe any of these two:

Code:

awk -v OFS="\t" '{$1=$1;sub(/%.*\)/, "", $4)}1' filename

perl -wnla -e '$F[3] =~ s/%.*\)// if $#F > 2; print join "\t", @F;' filename

if not, please, post the unadulterated output of the following command:

Code:

head filename | od -c

Aia,
Thank you so much - both of your latest solutions work.
As I am in the learning phase, please help me to interpret few of your magical coding.
I would appreciate if you can put few words for this piece of code:

1)
'{$1=$1;sub(/%.*\)/, "", $4)}1'
2)
perl -wnla -e '$F[3] =~ s/%.*\)// if $#F > 2; print join "\t", @F;'

As I suspected you do not use tabs between fields, you use multiple spaces imitating a tab.

awk

Code:

awk -v OFS="\t" '{$1=$1;sub(/%.*\)/, "", $4)}1' filename

-v OFS="\t" # sets the built-in Output Field Separator to a tab, instead of the default single space when outputting (which is used in the next part)

$1=$1 # changing a field rebuilds the $0 (whole record), which by default is a line, however the output separator is a tab now, substituting any conbination of spaces into a tab

sub(/%.*\)/, "", $4) # this is a built-in function in awk that takes three argument: 1st the regular expression to match, 2nd the string to substitute instead, and 3rd the field or string to look into it, in this case the 4th field.

1 # evaluate to true will print the default $0

Perl

Code:

perl -wnla -e '$F[3] =~ s/%.*\)// if $#F > 2; print join "\t", @F;' filename

-wnla -e # -w is for warnings, -n is for reading but not automatically printing, -l automatically adds an output separator after the print and when used in combination with -n (like here), it takes away any new line or input separator from the line, -a tells Perl to create an array name F and uses it to hold fields, -e tells Perl that what it comes next should be interpreted or executed as Perl code.

$F[3] =~ s/%.*\)// # take the 4th field stored in subscript 3 of array F and substitutes the first match of the regex between / and / with (empty) final /

if $#F > 2 # do the previous only if the array F has more than 3 elements (we are looking for the 4th)

print join "\t", @F # add new tab between each element stored in array F and then display it

Aia,
Simply awesome! The way you explained enlightened me. Your support is well appreciated as I am always trying to learn.
Thanks again.