1. h: Copy the original, pristine, unaltered line to the hold space, for future use.
2. s/=.*/=/: From the current line, remove everything that follows the equals sign inclusive, replacing it with just the equals sign. What remains is the variable name (with the trailing equals sign), in which we are not interested in substituting anything.
3. x: Store the variable name in the hold space by swapping the pattern and hold spaces. The original version of the line is now back in the pattern space.
4. s/^[^=]*=//: Remove all leading characters that are not an equals sign and the first equals sign, leaving nothing but the text of interest to the primary substitution operation.
5. s/change/different/g: Substitute each instance of "change" with "different" in the relevant text.
6. H: Append the resulting string to the variable name which we've kept tucked away in the hold space.
7. g: Copy the hold space to the pattern space.
8. s/\n//: Remove the newline that was inserted between the variable name and variable value by step 6's H command.
Last edited by alister; 05-27-2010 at 07:38 PM..
These 2 Users Gave Thanks to alister For This Post:
I am having a problem executing a sed substitute in a file. I have tried alot of different things I found in previous posts, however non seem to work.
I want to substitute this in $FILE:
VALUE=33.4
In the script I have tried the following:
prev=$(awk -F"=" '{ print $2 }' $FILE )
new=$(echo... (16 Replies)
Hi All,
I'm currently using SED to make various changes to some .xml files I'm working on, but I'm stuck on this particular problem.
I want to remove '<placeholder>element-name</placeholder>' from the following:
<heading>Element <placeholder>element-name</placeholder> not... (2 Replies)
I am trying to get rid of some ending tags but I run into some problems.
Ex.
How are you?</EndTag><Begin>It is fine.</Begin><New> Just about
I am trying to get rid of the ending tags, starts with </ and ending with >. (which is </EndTag> and </Begin>)
I tried the following
sed... (2 Replies)
I'm using sed to perform a simply search and replace. The typical data is:
<fig><image href="Graphics/BAV.gif" align="left" placement="break"
I need to replace the value in the first set of quotes, keeping the remainder of the line the same. Thus:
<fig><image href="NEW_VALUE" align="left"... (3 Replies)
Is there a way to substitute the URL-encoding references of ( & and ` ) with their actual appearance? for example....
%26 is &
say I want to convert every %26 in my file to &.....
awk '{gsub(/%26/,"&");print}'
Is there a way to do this?
I also want to be able to convert ` too! (3 Replies)
using awk to substitute data in a column delimited text file
hello i would like to use awk to do the following calculation from the following snippet.
input file
C;2390 ;CV BOUILLOTTE 2L 2FACES NERVUREES ;1.00 ;3552612239004;13417 ;25 ;50 ; 12;50000 ; ; ... (3 Replies)
Hello,
I have huge xml files and I need to replace only part of the data within a particular xml tag. This doesnt seem to be as simple as it sounds. I have searched everywhere and couldnt find any solution.
Ex:
In the below case I would like "def" to be replaced by "xyz" only when found in... (8 Replies)
I am trying to do what I thought should be a simple substitution, but I can't get it to work.
File:
Desire output:
I thought I'd start with a sed command to remove the part of the header line preceding the string "comp", then go on to remove the suffix of the target string (e.g. ":3-509(-)"),... (3 Replies)
Let me start off by saying I am a self taught sometimes scripter so what you will see below won't be pretty.
I have created a script to parse through a file with a large amount of data and simply pull out what I need. In doing this I create several files and then paste them together in order to... (2 Replies)
hi all,
i'd like to modify a file with sed , i want to substuite a char "-" with "/"
how can i do this?
Thanks for all
regards
Francesco (16 Replies)
Discussion started by: Francesco_IT
16 Replies
LEARN ABOUT V7
sed
SED(1) General Commands Manual SED(1)NAME
sed - stream editor
SYNOPSIS
sed [ -n ] [ -e script ] [ -f sfile ] [ file ] ...
DESCRIPTION
Sed copies the named files (standard input default) to the standard output, edited according to a script of commands. The -f option causes
the script to be taken from file sfile; these options accumulate. If there is just one -e option and no -f's, the flag -e may be omitted.
The -n option suppresses the default output.
A script consists of editing commands, one per line, of the following form:
[address [, address] ] function [arguments]
In normal operation sed cyclically copies a line of input into a pattern space (unless there is something left after a `D' command),
applies in sequence all commands whose addresses select that pattern space, and at the end of the script copies the pattern space to the
standard output (except under -n) and deletes the pattern space.
An address is either a decimal number that counts input lines cumulatively across files, a `$' that addresses the last line of input, or a
context address, `/regular expression/', in the style of ed(1) modified thus:
The escape sequence `
' matches a newline embedded in the pattern space.
A command line with no addresses selects every pattern space.
A command line with one address selects each pattern space that matches the address.
A command line with two addresses selects the inclusive range from the first pattern space that matches the first address through the next
pattern space that matches the second. (If the second address is a number less than or equal to the line number first selected, only one
line is selected.) Thereafter the process is repeated, looking again for the first address.
Editing commands can be applied only to non-selected pattern spaces by use of the negation function `!' (below).
In the following list of functions the maximum number of permissible addresses for each function is indicated in parentheses.
An argument denoted text consists of one or more lines, all but the last of which end with `' to hide the newline. Backslashes in text
are treated like backslashes in the replacement string of an `s' command, and may be used to protect initial blanks and tabs against the
stripping that is done on every script line.
An argument denoted rfile or wfile must terminate the command line and must be preceded by exactly one blank. Each wfile is created before
processing begins. There can be at most 10 distinct wfile arguments.
(1)a
text
Append. Place text on the output before reading the next input line.
(2)b label
Branch to the `:' command bearing the label. If label is empty, branch to the end of the script.
(2)c
text
Change. Delete the pattern space. With 0 or 1 address or at the end of a 2-address range, place text on the output. Start the
next cycle.
(2)d Delete the pattern space. Start the next cycle.
(2)D Delete the initial segment of the pattern space through the first newline. Start the next cycle.
(2)g Replace the contents of the pattern space by the contents of the hold space.
(2)G Append the contents of the hold space to the pattern space.
(2)h Replace the contents of the hold space by the contents of the pattern space.
(2)H Append the contents of the pattern space to the hold space.
(1)i
text Insert. Place text on the standard output.
(2)l List the pattern space on the standard output in an unambiguous form. Non-printing characters are spelled in two digit ascii, and
long lines are folded.
(2)n Copy the pattern space to the standard output. Replace the pattern space with the next line of input.
(2)N Append the next line of input to the pattern space with an embedded newline. (The current line number changes.)
(2)p Print. Copy the pattern space to the standard output.
(2)P Copy the initial segment of the pattern space through the first newline to the standard output.
(1)q Quit. Branch to the end of the script. Do not start a new cycle.
(2)r rfile
Read the contents of rfile. Place them on the output before reading the next input line.
(2)s/regular expression/replacement/flags
Substitute the replacement string for instances of the regular expression in the pattern space. Any character may be used instead
of `/'. For a fuller description see ed(1). Flags is zero or more of
g Global. Substitute for all nonoverlapping instances of the regular expression rather than just the first one.
p Print the pattern space if a replacement was made.
w wfile
Write. Append the pattern space to wfile if a replacement was made.
(2)t label
Test. Branch to the `:' command bearing the label if any substitutions have been made since the most recent reading of an input
line or execution of a `t'. If label is empty, branch to the end of the script.
(2)w wfile
Write. Append the pattern space to wfile.
(2)x Exchange the contents of the pattern and hold spaces.
(2)y/string1/string2/
Transform. Replace all occurrences of characters in string1 with the corresponding character in string2. The lengths of string1
and string2 must be equal.
(2)! function
Don't. Apply the function (or group, if function is `{') only to lines not selected by the address(es).
(0): label
This command does nothing; it bears a label for `b' and `t' commands to branch to.
(1)= Place the current line number on the standard output as a line.
(2){ Execute the following commands through a matching `}' only when the pattern space is selected.
(0) An empty command is ignored.
SEE ALSO ed(1), grep(1), awk(1)SED(1)