exract string between two different characters - Shell Programming and Scripting

rein · #1 05-06-2008

I want to extract a string from a line in a text file between two different characters:

for example:

:string"

I want to extract string. It has to be done in a one-liner.

fpmurphy · #2 05-06-2008

One way:

Code:

$ cat file
abc:string"def
$ sed -e 's/\(^.*:\)\(.*\)\(".*$\)/\2/' file
string
$

alamitab · #3 05-06-2008

echo ":string\"" | awk -F":" '{print $2}' | awk -F"\"" '{print $1}'

Franklin52 · #4 05-06-2008

Another one:

Code:

sed 's/.*:\(.*\)".*/\1/' file

Regards

drl · #5 05-06-2008

Hi.

With perl:

Code:

cat <<'EOF' |
Characters before :string" and characters after.
EOF
perl -wn -e 'print "$1\n" if m{[:](.*?)["]};'

Producing:

Code:

string

cheers, drl

radoulov · #6 05-06-2008

Do you need to handle multiple matches on one line?
Awk:

Code:

awk '$0=$2' FS=: RS=\"

Or:

Code:

perl -nle'print $1 while /:(.*?)\"/g'

drl · #7 05-06-2008

Hi.

The point raised by radoulov is a good one. Not all of the solutions produce the same results because of different assumptions:

Code:

#!/bin/bash -

# @(#) s3       Demonstrate comparison of solutions.

echo
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1) awk perl sed

cat <<'EOF' >data1
Characters before :string" and characters after, :another instance".
EOF

echo
echo " Input file data1:"
cat data1

echo
echo " Results of perl, left-most, shortest extraction:"
perl -wn -e 'print "$1\n" if m{[:](.*?)["]};' data1

echo
echo " Results of perl, longest extraction:"
perl -wn -e 'print "$1\n" if m{[:](.*)["]};' data1

echo
echo " Results of one sed solution:"
sed -e 's/\(^.*:\)\(.*\)\(".*$\)/\2/' data1

echo
echo " Results of another sed solution:"
sed 's/.*:\(.*\)".*/\1/' data1

echo
echo " Results of one awk solution:"
awk '$0=$2' FS=: RS=\" data1

echo
echo " Results of perl, all extractions (if -> while;g):"
perl -wn -e 'print "$1\n" while m{[:](.*?)["]}g;' data1

exit 0

Producing:

Code:

% ./s3

(Versions displayed with local utility "version")
Linux 2.6.11-x1
GNU bash 2.05b.0
GNU Awk 3.1.4
perl 5.8.4
GNU sed version 4.1.2

 Input file data1:
Characters before :string" and characters after, :another instance".

 Results of perl, left-most, shortest extraction:
string

 Results of perl, longest extraction:
string" and characters after, :another instance

 Results of one sed solution:
another instance

 Results of another sed solution:
another instance

 Results of one awk solution:
string
another instance

 Results of perl, all extractions (if -> while;g):
string
another instance

Which is another lesson for me in the usefulness of complete, non-ambiguous requirements ... cheers, drl

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