i need to pass a variable value to sed command. here is the description, what i am doing.
i am assigning a value to variable :
export ALSIZE=14420
$ echo $ALSIZE
14420
now i am using that value in sed command to read file from $ALSIZE line to end of the file. and i got the error
$ sed -n '$ALSIZE,$p' /db1/u04/oradata/GG11/ggserr.log
Unrecognized command: $ALSIZE,$p ====== >>
used the variable value in "" (double quotes) still got error.
$ sed -n '"$ALSIZE",$p' /db1/u04/oradata/GG11/ggserr.log
Unrecognized command: "$ALSIZE",$p ===== >>>
i am getting response back
$ sed -n '14420,$p' /db1/u04/oradata/GG11/ggserr.log
2013-12-26 06:36:17 INFO OGG-01026 Oracle GoldenGate Capture for Oracle, dpsbprd.prm: Rolling over remote file ./dirdat/siebel/r1003911.
2013-12-26 06:43:31 INFO OGG-01026 Oracle GoldenGate Capture for Oracle, dpsbprd.prm: Rolling over remote file ./dirdat/siebel/r1003912.
2013-12-26 11:07:47 INFO OGG-01026 Oracle GoldenGate Capture for Oracle, dpsbprd.prm: Rolling over remote file ./dirdat/siebel/r1003913.
what is the mistake i am doing. could you please advice ?
All of these would work:
sed -n $ALSIZE',$p' /db1/u04/oradata/GG11/ggserr.log
sed -n "$ALSIZE"',$p' /db1/u04/oradata/GG11/ggserr.log
sed -n "$ALSIZE,\$p" /db1/u04/oradata/GG11/ggserr.log
The key is understanding how quoting works:
You can quote part of a string or all of it: hello, hel'lo', 'hello', 'hel''lo' are all the same to the shell
Shell variables within double quotes are expanded to their value: "$ALSIZE" is expanded to "14420", which doesn't need to be quoted, so you could write simply $ALSIZE without quoting
Shell variables within single quotes are not expanded, so '$ALSIZE' will be used a the literal text "$ALSIZE" which is not what you want
In the "$ALSIZE,\$p" example the second $ has to be escaped to prevent the shell from expanding the $p variable, which probably has no value
The single quotes means that the '$' in $ALSIZE is expanded as a literal "\$ALSIZE". What happens if you rewrite it to:
sed -n $ALSIZE',$p' /db1/u04/oradata/GG11/ggserr.log
(leaving the single quotes until after the $ALSIZE variable)?
use double quotes:
kent$ s=5
kent$ seq 10 |sed -n "$s,$ p"
5
6
7
8
9
10
Related
Playing with makefile and bash shell scripting where I ended-up having a variable containing:
--global-option=build_ext --global-option=--b2-args=libtorrent-python-pic=on --global-option=--b2-args=address-model=32
I need to convert it so double-quotes gets appended at the right place such as:
--global-option=build_ext --global-option=--b2-args="libtorrent-python-pic=on" --global-option=--b2-args="address-model=32"
I tried the following without success:
echo $myvar | sed -e 's/ /\n/' | sed -z '{s/=/="/2;t;s/$/"/}'
--global-option=build_ext
--global-option="--b2-args=libtorrent-python-pic=on
EDIT: Note that this time it's --b2-args= but this could be a conjunction of --anything=, and the reason why I was focussing on the second instance of = to change for =" and if true append = at the end of word.
Since your question doesn't discuss anything about prepending --global-option= if it's missing as in the final --b2-args... string on the provided input line, I think your input was really supposed to be:
$ cat file
--global-option=build_ext --global-option=--b2-args=libtorrent-python-pic=on --global-option=--b2-args=address-model=32
in which case using any sed in any shell on every Unix box:
$ sed 's/\([^ =]*=[^= ]*=\)\([^ ]*\)/\1"\2"/g' file
--global-option=build_ext --global-option=--b2-args="libtorrent-python-pic=on" --global-option=--b2-args="address-model=32"
I already know that sed uses own approach to deal with single quote but I think it still possible to use it in my automation script.
I had to replace value of fingerprint in Saltstack config file.
Current value:
#master_finger: ''
Target value
master_finger: 'some:value'
My current command which doesn't work:
$ sed -i 's/#master_finger: ''/master_finger: 'some:value'/g' /etc/salt/minion
returns:
master_finger: some:value''
How can I solve this?
just use the double quotes to enclose the script.
$ echo "#master_finger: ''" | sed "s/#master_finger: ''/master_finger: 'some:value'/"
master_finger: 'some:value'
It's not sed that's making handling of 's difficult, it's the shell because the shell does not allow 's within any '-quoted string, including scripts.
You could save the sed script in a file and run it with -f or use a here document:
$ sed -f- file <<'EOF'
s/#master_finger: ''/master_finger: 'some:value'/g
EOF
master_finger: 'some:value'
To see the difference between the above and #karakfas suggestion:
$ sed -f- file <<'EOF'
s/#master_finger: ''/master_finger: '$(date)'/g
EOF
master_finger: '$(date)'
$ sed "s/#master_finger: ''/master_finger: '$(date)'/" file
master_finger: 'Sun Feb 14 06:50:43 CST 2021'
and imagine if date was replace by rm -rf * or something worse.
Also consider:
$ sed 's/#master_finger: '\'\''/master_finger: '\''$(date)'\''/' file
master_finger: '$(date)'
How to find structures matching a pattern
struct struct_name {
....
....
};
I'm using
sed -n -e '/struct{/,/}/p'
how to search for any struct_name
To extract all struct definitions (POSIX-compliant command):
sed -n '/struct [^ {]\{1,\} {/,/}/p' file
More robust with respect to whitespace variations (POSIX-compliant):
sed -n '/struct[[:blank:]]\{1,\}[^ {]\{1,\}[[:blank:]]*{/,/}/p' file
Alternative, using an extended regular expression (works with both GNU and BSD/macOS sed):
sed -E -n '/struct[[:blank:]]+[^ {]+[[:blank:]]*\{/,/\}/p' file
awk alternative (awk only uses extended regexes):
awk '/struct[[:blank:]]+[^ {]+[[:blank:]]*\{/,/\}/' file
The awk solution has the added advantage that a given struct definition will also be extracted correctly if it is all on a single line: awk looks for the end of a range on the same input line as the start of the range, whereas sed does not.
To extract a specific struct definition by name:
sed doesn't support variables, so your best bet is to splice in a shell variable that the shell expands up front.
name='struct_name' # define name to search for as shell var.
sed -n '/struct '"$name"' {/,/}/p' file # splice shell var. into sed script
Note that I've deliberately not used sed -n "/struct $name {/,/}/p" - a single, double-quoted string expanded by the shell as a whole - so as to make it clear which part of the sed script is expanded by the shell up front.
This works in this simple case, but is tricky business in general, because you must ensure that the expanded variable value contains no regex/sed metacharacters that break the command.
Here's an awk alternative that uses awk variables and literal substring matching to bypass the problem of potentially having to escape the variable value:
awk -v name='struct_name' 'index($0, "struct " name " {"),/}/' file
This solution has the added advantage that the struct definition will also be extracted correctly if it is all on a single line: awk looks for the end of a range on the same input line as the start of the range, whereas sed does not.
This will search a text file for struct_name. You can use the -E switch to use a regular expression.
grep -no struct_name test.txt
The -n switch causes the line number to be included, the -o means only the matching element of the line will be displayed.
sed does not print line 1 to line 545.The result of the following command is empty resultfile.txt. Can someone say what should be the correct command?
RESULT=545;sed -n '1, $RESULT p' Configuration.txt > resultfile.txt
The above is not a sed issue, but rather a shell issue: you used single quotes, which inhibit variable expansion.
$ echo '$PWD'
$PWD
$ echo $PWD
/tmp
$ echo "$PWD"
/tmp
Either no quotes at all, or double quotes, allows the shell to expand variables. (No quotes at all means the shell expands everything; double quotes inhibit globbing, redirections, and such.)
Use double quotes so that $RESULT is expanded:
RESULT=545;sed -n "1, $RESULT p" Configuration.txt > resultfile.txt
By the way, the following would be simpler:
head -$RESULT Configuration.txt > resultfile.txt
And, if your file is big, this will quit as soon as you reach line 545 and be more efficient:
sed ${RESULT}q Configuration.txt > resultfile.txt
This question already has answers here:
Using different delimiters in sed commands and range addresses
(3 answers)
Closed 1 year ago.
I have a Visual Studio project, which is developed locally. Code files have to be deployed to a remote server. The only problem is the URLs they contain, which are hard-coded.
The project contains URLs such as ?page=one. For the link to be valid on the server, it must be /page/one .
I've decided to replace all URLs in my code files with sed before deployment, but I'm stuck on slashes.
I know this is not a pretty solution, but it's simple and would save me a lot of time. The total number of strings I have to replace is fewer than 10. A total number of files which have to be checked is ~30.
An example describing my situation is below:
The command I'm using:
sed -f replace.txt < a.txt > b.txt
replace.txt which contains all the strings:
s/?page=one&/pageone/g
s/?page=two&/pagetwo/g
s/?page=three&/pagethree/g
a.txt:
?page=one&
?page=two&
?page=three&
Content of b.txt after I run my sed command:
pageone
pagetwo
pagethree
What I want b.txt to contain:
/page/one
/page/two
/page/three
The easiest way would be to use a different delimiter in your search/replace lines, e.g.:
s:?page=one&:pageone:g
You can use any character as a delimiter that's not part of either string. Or, you could escape it with a backslash:
s/\//foo/
Which would replace / with foo. You'd want to use the escaped backslash in cases where you don't know what characters might occur in the replacement strings (if they are shell variables, for example).
The s command can use any character as a delimiter; whatever character comes after the s is used. I was brought up to use a #. Like so:
s#?page=one&#/page/one#g
A very useful but lesser-known fact about sed is that the familiar s/foo/bar/ command can use any punctuation, not only slashes. A common alternative is s#foo#bar#, from which it becomes obvious how to solve your problem.
add \ before special characters:
s/\?page=one&/page\/one\//g
etc.
In a system I am developing, the string to be replaced by sed is input text from a user which is stored in a variable and passed to sed.
As noted earlier on this post, if the string contained within the sed command block contains the actual delimiter used by sed - then sed terminates on syntax error. Consider the following example:
This works:
$ VALUE=12345
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
MyVar=12345
This breaks:
$ VALUE=12345/6
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
sed: -e expression #1, char 21: unknown option to `s'
Replacing the default delimiter is not a robust solution in my case as I did not want to limit the user from entering specific characters used by sed as the delimiter (e.g. "/").
However, escaping any occurrences of the delimiter in the input string would solve the problem.
Consider the below solution of systematically escaping the delimiter character in the input string before having it parsed by sed.
Such escaping can be implemented as a replacement using sed itself, this replacement is safe even if the input string contains the delimiter - this is since the input string is not part of the sed command block:
$ VALUE=$(echo ${VALUE} | sed -e "s#/#\\\/#g")
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
MyVar=12345/6
I have converted this to a function to be used by various scripts:
escapeForwardSlashes() {
# Validate parameters
if [ -z "$1" ]
then
echo -e "Error - no parameter specified!"
return 1
fi
# Perform replacement
echo ${1} | sed -e "s#/#\\\/#g"
return 0
}
this line should work for your 3 examples:
sed -r 's#\?(page)=([^&]*)&#/\1/\2#g' a.txt
I used -r to save some escaping .
the line should be generic for your one, two three case. you don't have to do the sub 3 times
test with your example (a.txt):
kent$ echo "?page=one&
?page=two&
?page=three&"|sed -r 's#\?(page)=([^&]*)&#/\1/\2#g'
/page/one
/page/two
/page/three
replace.txt should be
s/?page=/\/page\//g
s/&//g
please see this article
http://netjunky.net/sed-replace-path-with-slash-separators/
Just using | instead of /
Great answer from Anonymous. \ solved my problem when I tried to escape quotes in HTML strings.
So if you use sed to return some HTML templates (on a server), use double backslash instead of single:
var htmlTemplate = "<div style=\\"color:green;\\"></div>";
A simplier alternative is using AWK as on this answer:
awk '$0="prefix"$0' file > new_file
You may use an alternative regex delimiter as a search pattern by backs lashing it:
sed '\,{some_path},d'
For the s command:
sed 's,{some_path},{other_path},'