awk/sed with special characters

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting awk/sed with special characters
# 1  
Old 05-03-2002
awk/sed with special characters

i have this script that searches for a pattern.
However it fails if the pattern includes some
special characters. So far, it fails with the
following strings:
1. -Cr
2. $Mj
3. H'412
would a sed or awk be more effective?
i don't want the users to put the (\)
during the search (they are not familiar with unix)...
help is very much appreciated!


case $# in
0) echo "\n\t No argument(s) entered! Try again."
echo "\t Usage: whereis arg1 [arg2] [arg3]"
exit 1 ;;
*) grep -n "$*" file | cut -f1 -d: > lineno
cat lineno ;;

if sed/awk can be used, how can i print the line numbers?
# 2  
Old 05-03-2002
The shell does processing to command lines long before it invoke the command. A command like:
something $xyz
is just not going to fly. The shell is going to look for a variable called xyz and substitute that value. Compare the above command to:
echo $PATH

The variable names are gone before the command runs.

Maybe you could read in the string instead of entering it on the command line?
#! /usr/bin/ksh
print -n "enter search string -"
read string
sed -n '/'"${string}"'/=' < file
exit 0

should do it if you just want only the line number printed.
# 3  
Old 05-03-2002
Thanks Perderabo!

i tried your code and it works great. although i had an error
when i entered the string df/DF.

apalex>cat infile
pattern1 $Major
pattern2 -Crit
pattern3 df/DF
pattern4 h'405
pattern5 \ffe
pattern6 ab >
pattern7 abc >>
pattern8 A"a"
pattern9 `0de`

apalex> cat whereis
#! /usr/bin/ksh
print -n "enter search string -"
read string
sed -n '/'"${string}"'/=' < infile
exit 0

apalex> whereis
enter search string -df/DF
sed: command garbled: /df/DF/=

I just thought its easier to type the string on the
command line, so i tried to insert your code in
my script but it really gives me a lot of errors...

apalex> cat whereis1
case $# in
0) echo "\n\t No pattern(s) entered! Try again."
echo "\t Usage: whereis1 pattern1 [pattern2]"
exit 1 ;;
*) sed -n '/'"${*}"'/=' < infile
exit 0 ;;

it doesn't work on patterns:
$Major, ab > and abc >>

I really appreciate this forum, gives me a chance to improve my
skills. Thanks a lot guys!!!
# 4  
Old 05-06-2002
Perderabo, can you please explain further the line below?
i can't follow the logic of using ", ' ,= and {} on the sed.

sed -n '/'"${string}"'/=' < infile

Is there any fix in the code for searching for string with "/" on it?
Please see below. Thank you.
# 5  
Old 05-06-2002
Well ${string} is a variable reference like $string but more secure for adjacent characters. I could probable get away with just $string in this case.

I put the variable refernce in double quotes to protect any white space in the value. Everything else in the sed command is in single quotes to prevent anything at all from happening to them.

But the quotes and braces are shell things not sed things. sed will never see them.

As for dealing with the slash, it is possible but would require so much code that I would drop ksh and switch to c. When a script becomes more complex than the c program would be, it's time to switch languages.
# 6  
Old 05-06-2002
Thanks for the info!
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

sed in a while loop with special characters

I have the foolowing data file: File1 <p name="A">5004</p> <p name="B">5004</p> <p name="C">5004</p> <p name="A">15004</p> <p name="B">15004</p> <p name="C">15004</p> In a while loop using sed (100 of line need to be replace), I need the output to File3:... (2 Replies)
Discussion started by: bobo
2 Replies

2. Shell Programming and Scripting

sed special characters issues

I am dusting off the sed cobwebs and had a basic question: I have a file that contains: $firewall = "on"; $cache = "on"; $dataset{'mary had a little lamb'} = "on"; and want to only change the contents of what is between the single quotes: $dataset{'big bad wolf'} = "on"; I... (3 Replies)
Discussion started by: metallica1973
3 Replies

3. Shell Programming and Scripting

Sed - remove special characters

Hi, I have a file with this line, it's always in the first line: I want to remove these special characters: ╗┐ file1 ╗┐\\bar\c$\test2\;3.348.118 Bytes;160 ;3 \\bar\c$\test\;35 Bytes;2 ;1 I want the same file to be only \\bar\c$\test2\;3.348.118 Bytes;160 ;3 \\bar\c$\test\;35... (4 Replies)
Discussion started by: nakaedu
4 Replies

4. Shell Programming and Scripting

Escape special characters in SED

Need help in escaping special characters in sed command. Here is the the string which i am trying to find a replace with From :- REQUEST_TYPE=PIXEL&amp;MSG_ID={//MESSAGE_ID} To :- REQUEST_TYPE=PIXEL&amp;MSG_ID= X_EDELIVERY_MESSAGE_ID &amp; BATCH_ID= X_EDELIVERY_BATCH_ID Here is the sed command i am... (2 Replies)
Discussion started by: aakishore
2 Replies

5. Shell Programming and Scripting

Need help with sed to escape special characters

Hello Everyone, I need to read an encrypted password from the user and update that value in an xml file. I am trying to use "sed" for searching the appropriate tag and replacing this new value that get from the user. Since the encrypted password can contain special characters(like /,\,&,etc),... (4 Replies)
Discussion started by: majose
4 Replies

6. Shell Programming and Scripting

Sed or awk : pattern selection based on special characters

Hello All, I am here again scratching my head on pattern selection with special characters. I have a large file having around 200 entries and i have to select a single line based on a pattern. I am able to do that: Code: cat mytest.txt | awk -F: '/myregex/ { print $2}' ... (6 Replies)
Discussion started by: usha rao
6 Replies

7. Shell Programming and Scripting

SED with Special characters

Hello All Seeking the right one SED command. My attempt is: From orginal.txt by SED to target.txt sed -i "/('outbound-callerid/a\$ext->add($context, $exten, '', new ext_SipAddHeader('P-Preferred-Identity', '<sip:${CALLERID(nummer)}>'));" orginal.txtWhat am make wrong?:wall: ... (5 Replies)
Discussion started by: mdbinder
5 Replies

8. Shell Programming and Scripting

Using sed to replace special characters

Hi everyone I have file1 contains: '7832' ' 8765 6543 I want a sed command that will format as: '7832' , '8765' , '6543' I tried sed -e s/\'//g -e 's/^*//;s/*$//' file1 > file2 sed -e :a -e '$!N; s/\n/ /; ta' file2 which gives: 7832 8765 6543 I need some help to continue with... (5 Replies)
Discussion started by: nimo
5 Replies

9. Shell Programming and Scripting

sed with many special characters

I started with this: counter1=1 cp file.txt file_${counter1}.tmp while read name1 do echo $name1 counter2=`expr $counter1 + 1` sed /'${name1}'/d file_${counter1}.txt > file_${counter2}.txt counter1=`expr $counter1 + 1` done < source.txtsource.txt contains the... (1 Reply)
Discussion started by: lakanino
1 Replies

10. Shell Programming and Scripting

sed with special characters

Hi, I am reading a file (GC_JAR.log) which has entries like: 511725.629, 0.1122672 secs] 525268.975, 0.1240036 secs] 527181.835, 0.2068215 secs] 527914.287, 0.2884801 secs] 528457.134, 0.2548725 secs] I want to replace all the entries of "secs]" with just "secs" Thus, the output... (4 Replies)
Discussion started by:
4 Replies
Login or Register to Ask a Question