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Grepping for Exact Strings

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# 15  
Old 04-13-2009
working solution.
Here you go:

My input file "a" contains:

Code:
my-do-not-change-airplane and other frogs
airplane.seriously change me
sometimes in the file i'm using,
there are words like this: db-airplane, db-12.airplane.
in cases like that, your code turns
the words into db-helicopter, db-12.helicopter.
airplane,frogs,somewerirdairplane buggly buggly
aardvark,chameleon,airplane,dugong,basilisk
aardvark,chameleon,dugong,basilisk,airplane

My script, "clam" looks like this:

Code:
#!/bin/ksh
#----------------------------------------------------------------------#
# Find funky occurances of airplane...                                 #
#----------------------------------------------------------------------#
cat a |
#----------------------------------------------------------------------#
# Translate any and word delimiters to newlines...                     #
#----------------------------------------------------------------------#
  tr '[. ,      ]' '\012\012\012\012' |
  grep airplane |
#----------------------------------------------------------------------#
# Grep OUT our target word to change...                                #
#----------------------------------------------------------------------#
  grep -v "^airplane$" |
  sort -u |
while read pattern ; do
#----------------------------------------------------------------------#
# Create list of sed commands...                                       #
#----------------------------------------------------------------------#
  print "s/$pattern/${pattern}DONOTEDIT/g;"
done > sed.file
#----------------------------------------------------------------------#
# Finish our little sed script. Remove our DONOTEDIT strings.          #
#----------------------------------------------------------------------#
cat << EOF >> sed.file
s/\<airplane\>/HELICOPTER/g;
s/DONOTEDIT//g;
EOF
#----------------------------------------------------------------------#
# ... and voila....                                                    #
#----------------------------------------------------------------------#
sed -f sed.file a

... and the output is:

Code:
my-do-not-change-airplane and other frogs
HELICOPTER.seriously change me
sometimes in the file i'm using,
there are words like this: db-airplane, db-12.HELICOPTER.
in cases like that, your code turns
the words into db-helicopter, db-12.helicopter.
HELICOPTER,frogs,somewerirdairplane buggly buggly
aardvark,chameleon,HELICOPTER,dugong,basilisk
aardvark,chameleon,dugong,basilisk,HELICOPTER

# 16  
Old 04-13-2009
I see that the script also changed db-12.airplane to db-12.HELICOPTER.

You can modify this action, one of two ways:

remove the . from the "tr" translation list, ( also removing one of the \012 sequences.
btw, you need to match word-delimiter count to \012 count. )

Or simply intercept the sed.file and modify its contents first.
# 17  
Old 04-13-2009
anyways.... removed the . word delimiter. here's the code:

Code:
#!/bin/ksh

#----------------------------------------------------------------------#
# Find funky occurances of airplane...                                 #
#----------------------------------------------------------------------#
cat a |

#----------------------------------------------------------------------#
# Translate any and word delimiters to newlines...                     #
#----------------------------------------------------------------------#
  tr '[ ,       ]' '\012\012\012' |
  grep airplane |

#----------------------------------------------------------------------#
# Grep OUT our target word to change...                                #
#----------------------------------------------------------------------#
  grep -v "^airplane$" |
  sort -u |
while read pattern ; do

#----------------------------------------------------------------------#
# Create list of sed commands...                                       #
#----------------------------------------------------------------------#
  print "s/$pattern/${pattern}DONOTEDIT/g;"

done > sed.file

#----------------------------------------------------------------------#
# Finish our little sed script. Remove our DONOTEDIT strings.          #
#----------------------------------------------------------------------#
cat << EOF >> sed.file
s/\<airplane\>/HELICOPTER/g;
s/DONOTEDIT//g;
EOF

#----------------------------------------------------------------------#
# ... and voila....                                                    #
#----------------------------------------------------------------------#
sed -f sed.file a

# 18  
Old 04-19-2009
I spent some time trying to get into awk. So, here is my solution:
Code:
awk 'BEGIN {FS="[.,\ ]"; OFS=" ";} {for(i=1; i<=NF; ++i) {if($i=="airplane") {sub(/airplane/, "helicopter", $i);}} print $0;}' airplane > airplane.new

There's a small flaw in it, though, due to the fact that the input field delimiter (FS) is a regular expression instead of a static string/character. Unfortunately, I didn't find a way to "preserve" the actual input delimiter for output (OFS) but had to set it to a static (whitespace) character.

Maybe one of you guys knows a way how to achieve this. Smilie

--Gunther
# 19  
Old 04-19-2009
Skysmart, you have to be more precise about what is your definition for "airplane alone".
Given this definition, it should be feasible to do the replacement with sed alone, no pun intended.

Usually the definition for "word" is: a sequence of alfanumeric characters surrounded by punctuation characters or by the start/end of the line.
Usually the definition for alfanumeric is: 0,1,...9,a,b,...z,A,B,...Z,_
Usually the definition for punctuation is: any non alfanumeric character.

I understand that you assume that the character "-" is not punctuation.
Is there any other character that you deem not punctuation?

Code:
sed -r 's/(^|[^0-9a-zA-Z_-])airplane([^0-9a-zA-Z_-]|$)/\1helicopter\2/g'

Tested with GNU sed version 4.1.5.

-r is to make sed understand extended regular expression syntax.
^ stands for the start of the line and $ stands for the end of the line; they are "anchors" and do not represent a character.
| is the alternating operator, that is multiple choices.
[] is a class of characters; this expression represents a single character; [^...] is the class of characters that are not in the class [...].
\1 and \2 are backreferences and they are required to keep the characters surrounding the airplane.
Last edited by colemar; 04-19-2009 at 09:43 AM..
# 20  
Old 04-19-2009
Quote:
Originally Posted by SkySmart
...
you see what i'm saying? I dont want the code to touch anything in the file that isn't "airplane", alone. all i want is to replace places were the airplane stands alone.

thanks you so much for your suggestions

If I correctly understand the OP's request, here goes another way with perl,

In my test file, highlighted words contain the required pattern, but only those surrounded by whitespace, or that are found at the start or end of the record (in bold) are to be replaced:

Code:
$ cat file
data data data data airplane. data data data data data data airplane data data

data airplane. data airplanewomen, airplaneman, sweetairplane, sourairplane.

airplane data data data data data data data data data db-airplane, db-12.airplane.

data data airplane, data data data data data data wantairplane data airplane

data data data data airplane data data data data data .airplane data data data


Code:
perl -ne 's/(^|(?<=\s))airplane((?=\s)|$)/helicopter/g; print' file


Output:

Code:
data data data data airplane. data data data data data data helicopter data data

data airplane. data airplanewomen, airplaneman, sweetairplane, sourairplane.

helicopter data data data data data data data data data db-airplane, db-12.airplane.

data data airplane, data data data data data data wantairplane data helicopter

data data data data helicopter data data data data data .airplane data data data

Tested with perl v5.10.0 (Linux) and v5.8.4 (Solaris 10).
# 21  
Old 04-20-2009
rubin -- could you explain the pipe and stuff?
I don't see why you left off the < on the end-of-line expression.
or what the question mark is doing...

Code:
s/(^|(?<=\s))airplane((?=\s)|$)/helicopter/g;

Thanks,
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