Aia, while you point out good practice concerning this (and thanks, indeed), Don seems to be hinting at something much more. Still trying to get a grip on this stuff...
Along those lines, I discovered the need for sed to use "" in the context of passing strings (variable expansion) a couple of turns back. I did have some initial reservations about EOL delimiter usage in that context, until I realized that the $ would always find itself next to /; thereby providing a marker for sed to make the correct implementation. So far, so good.
But I can't even begin to imagine how the internal code would look to allow all of these variants,
to function without any variation whatsoever...
Aia, while you point out good practice concerning this (and thanks, indeed), Don seems to be hinting at something much more. Still trying to get a grip on this stuff...
Along those lines, I discovered the need for sed to use "" in the context of passing strings (variable expansion) a couple of turns back. I did have some initial reservations about EOL delimiter usage in that context, until I realized that the $ would always find itself next to /; thereby providing a marker for sed to make the correct implementation. So far, so good.
But I can't even begin to imagine how the internal code would look to allow all of these variants,
to function without any variation whatsoever...
You're missing the point. With all of the above command lines, sed gets exactly the same four arguments: sed, -i, s/\${HOUSING}/casing/g, and ./some.file.
The quote processing is done by the shell before it invokes sed.
This User Gave Thanks to Don Cragun For This Post:
So, in net, are the oft-called single quotes even necessary for most sed command syntax? It seems as though they're being factored out across the board...
As I mentioned in post #7, you want to use single quote surrounding the command code to protect it from whatever the shell does first. If you know absolutely, how the shell is going to treat that code and would not affect it, you don't even need any quoting, or you could even scape everything you know the shell is going to treat as an special character, and use no quotes.
Dont' want to take away your AHA! moment, but I was trying to convince of the opposite. As a rule of thumb, single quote always, unless the shell needs to see the variable to substitute. In those cases, the game of double quote, scape, multiple single quotes would be on.
I am learning SED and just following the shell scripting book, i have trouble understanding the grep and sed statement,
Question : 1
__________
/opt/oracle/work/antony>cat teledir.txt
jai sharma 25853670
chanchal singhvi 9831545629
anil aggarwal 9830263298
shyam saksena 23217847
lalit... (7 Replies)
Hi,
I am running a script sample.sh in bash environment .In the script i am using sed and awk commands which when executed individually from terminal they are getting executed normally but when i give these sed and awk commands in the script it is giving the below errors :-
./sample.sh: line... (12 Replies)
My need is :
Want to change
docBase="/something/something/something"
to
docBase="/only/this/path/for/all/files"
I have some (about 250 files)xml files.
In FileOne it contains
<Context path="/PPP" displayName="PPP" docBase="/home/me/documents" reloadable="true" crossContext="true">... (1 Reply)
I'm not sure if the problem I'm seeing is an artifact of sed or simply a beginner's mistake. Here's the problem: I want to add a zero-width space following each underscore between XML tags. For example, if I had the following xml:
<MY_BIG_TAG>This_is_a_test</MY_BIG_TAG>
It should look like... (8 Replies)
Hi all,
First off, Thank you all for the knowledge I have gleaned from this site!
Deleting Records from a text file... sed paragraphs
The following code works nearly perfect, however each time it is run on the log file it adds a newline at the head of the file, run it 5 times, it'll have 5... (1 Reply)
i made a script to update a lot of xml files. to save me some time. Ran it and it replaced all the the files with a 0kb file. The problem i was having is that I am using sed to change xml node <doc_root>. The problem with this is it has a / in the closing xml tag and the stuff inside will also have... (4 Replies)
Hello and thx for reading this
I'm using sed to remove only the leading spaces in a file
bash-280R# cat foofile
some text
some text
some text
some text
some text
bash-280R#
bash-280R# sed 's/^ *//' foofile > foofile.use
bash-280R# cat foofile.use
some text
some text
some text... (6 Replies)
Write a sed script to extract the year, rank, and stock for the most recent 10 years available in the file top10_mktval.csv, and output in the following format:
------------------------------
YEAR |RANK| STOCK
------------------------------
2007 | 1 | Exxon... (1 Reply)