Ok I guess I need something that will do the following:
search for this line of code in /var/lib/asterisk/bin/retrieve_conf:
$engineinfo = engine_getinfo();
insert these two lines immediately following:
$engineinfo['engine']="asterisk";
$engineinfo['version']="1.6.2.11";
Thanks in advance,
Joe
You could do it like this
sed -ne '/$engineinfo = engine_getinfo();/a\'$'\n''$engineinfo['engine']="asterisk";\'$'\n''$engineinfo['version']="1.6.2.11";'$'\n'';p' /var/lib/asterisk/bin/retrieve_conf
Add -i for modification in place once you confirm that it works.
What does it do and how does it work?
First we tell sed to match a line containing your string. On that matched line we then will perform an a command, which is "append text".
The syntax of a sed a command is
a\
line of text\
another line
;
Note that the literal newlines are part of this syntax. To make it all one line (and preserve copy-paste ability) in place of literal newlines I used $'\n' which will tell bash or zsh to insert a real newline in place. The quoting necessary to make this work is a little complex: You have to exit single-quotes so that you can have the $'\n' be interpreted by bash, then you have to re-enter a single-quoted string to prevent bash from interpreting the rest of your input.
EDIT: Updated to append both lines in one append command.
You can use Perl and Tie::File (included in the Perl distribution):
use Tie::File;
tie my #array, 'Tie::File', "/var/lib/asterisk/bin/retrieve_conf" or die $!;
for (0..$#array) {
if ($array[$_] =~ /\$engineinfo = engine_getinfo\(\);/) {
splice #array, $_+1, 0, q{$engineinfo['engine']="asterisk"; $engineinfo['version']="1.6.2.11";};
last;
}
}
Just for the sake of symmetry here's an answer using awk.
awk '{ if(/\$engineinfo = engine_getinfo\(\);/) print $0"\n$engineinfo['\''engine'\'']=\"asterisk\";\n$engineinfo['\''version'\'']=\"1.6.2.11\"" ; else print $0 }' in.txt
You may also use ed:
# cf. http://wiki.bash-hackers.org/howto/edit-ed
cat <<-'EOF' | ed -s /var/lib/asterisk/bin/retrieve_conf
H
/\$engineinfo = engine_getinfo();/a
$engineinfo['engine']="asterisk";
$engineinfo['version']="1.6.2.11";
.
wq
EOF
A Perl one-liner:
perl -pE 's|(\$engineinfo) = engine_getinfo\(\);.*\K|\n${1}['\''engine'\'']="asterisk";\n${1}['\''version'\'']="1.6.2.11";|' file
sed -i 's/$engineinfo = engine_getinfo();/$engineinfo = engine_getinfo();<CTRL V><CNTRL M>$engineinfo['engine']="asterisk"; $engineinfo['version']="1.6.2.11";/' /var/lib/asterisk/bin/retrieve_conf
Related
I try to use sed to replace a word in a 2-line pattern with another word. When in one line the pattern 'MACRO "something"' is found then in the next line replace 'BLOCK' with 'CORE'. The "something" is to be put into a reference and printed out as well.
My input data:
MACRO ABCD
CLASS BLOCK ;
SYMMETRY X Y ;
Desired outcome:
MACRO ABCD
CLASS CORE ;
SYMMETRY X Y ;
My attempt in sed so far:
sed 's/MACRO \([A-Za-z0-9]*\)/,/ CLASS BLOCK ;/MACRO \1\n CLASS CORE ;/g' input.txt
The above did not work giving message:
sed: -e expression #1, char 30: unknown option to `s'
What am I missing?
I'm open to one-liner solutions in perl as well.
Thanks,
Gert
Using a perl one-liner in slurp mode:
perl -0777 -pe 's/MACRO \w+\n CLASS \KBLOCK ;/CORE ;/g' input.txt
Or using a streaming example:
perl -pe '
s/^\s*\bCLASS \KBLOCK ;/CORE ;/ if $prev;
$prev = $_ =~ /^MACRO \w+$/
' input.txt
Explanation:
Switches:
-0777: Slurp files whole
-p: Creates a while(<>){...; print} loop for each line in your input file.
-e: Tells perl to execute the code on command line.
When in one line the pattern 'MACRO "something"' is found then in the
next line replace 'BLOCK' with 'CORE'.
sed works on lines of input. If you want to perform substitution on the next line of a specified pattern, then you need to add that to the pattern space before being able to do so.
The following might work for you:
sed '/MACRO/{N;s/\(CLASS \)BLOCK/\1CORE/;}' filename
Quoting from the documentation:
`N'
Add a newline to the pattern space, then append the next line of
input to the pattern space. If there is no more input then sed
exits without processing any more commands.
If you want to make use of address range as in your attempt, then you need:
sed '/MACRO/,/CLASS BLOCK/{s/\(CLASS\) BLOCK/\1 CORE/}' filename
I'm not sure why do you need a backreference for substituting the macro name.
You could try this awk command also,
awk '{print}/MACRO/ {getline; sub (/BLOCK/,"CORE");{print}}' file
It prints all the lines as it is and do the replacing action on seeing a word MACRO on a line.
Since getline has so many pitfall I try not to use it, so:
awk '/MACRO/ {a++} a==1 {sub(/BLOCK/,"CORE")}1' file
MACRO ABCD
CLASS CORE ;
SYMMETRY X Y ;
This could do it
#!awk -f
BEGIN {
RS = ";"
}
/MACRO/ {
sub("BLOCK", "CORE")
}
{
printf s++ ? ";" $0 : $0
}
"line" ends with ;
sub BLOCK for CORE in "lines" with MACRO
print ; followed by "line" unless first line
I have this line about 500 times in a my file backup.xml
my-company-review/</link>
Is there a way through command line, perl, etc. to add a number into the line after the word review. For example, something like this:
my-company-review1/</link>
my-company-review2/</link>
my-company-review3/</link>
Thanks in advance for the help!
Why not use Perl, as I suggested with your last problem. Once again, this is a sort of hack solution, that only works if there's a maximum of one replacement per line... But it's a quick throw-away program.
perl -e '$count=1; foreach (<>) { s/(my-company-review)(\/<\/link>)/$1$count$2/ && $count++; print; }'
An extra loop will do multiple substitutions on a line:
perl -e '$count=1; foreach (<>) { while(s/(my-company-review)(\/<\/link>)/$1$count$2/) {$count++;} print; }'
That awk solution looks way nicer =)
Here's one way:
perl -i -wpe ' BEGIN { $count = 1; }
++$count
if s{(my-company-review)(/</link>)}{$1$count$2};
' backup.xml
(Disclaimer: not tested.)
You can use awk:
awk 'gsub("/</link>", NR "/</link>")' infile
or perl:
perl -ne 's:/</link>:$./</link>:; print' infile
I am not very proficient in perl, awk, or sed and I have been searching the web for a solution to my problem for some while now, but wasn't very successful.
I would like to replace
<math> ... </math>
with
<math>\begin{align} ... \end{align}</math>
if ... contains \\. My problem is that the string between the <math> tags can span multiple lines. I managed to replace the tags within one line with sed but couldn't get it to run for multiple lines.
Any simple solution with perl, awk, or sed is very welcome. Thanks a lot.
Use separate expressions for each tag and the script will be immune to multilinedness:
sed -e 's,<math>,&\\begin{align},g' -e 's,</math>,&\\end{align},g'
Edit:
Multiline awk version:
awk '/<math>/,/<\/math>/ {
if (index($0, "<math>")) {
a=$0
} else {
b = b $0
}
if (index($0, "</math>")) {
if (index(b,"\\\\")) {
sub("<math>","&\\begin{align}", a)
sub("</math>","\\end{align}&", b)
};
print a,b
a=""
b=""
}
}'
Try next perl command. How it works? It reads content file in slurp mode saving it in $f variable and later add with a regexp in single mode (match newlines with .) \begin{regex} and \end{regex} if found \\ between math tags.
perl -e '
do {
$/ = undef;
$f = <>
};
$f =~ s#(<math>)(.*\\\\.*)(</math>)#$1\\begin{align}$2\\end{align}$3#s;
printf qq|%s|, $f
' infile
This might work for you (GNU sed):
sed ':a;$!{N;ba}
/[\x00\x01\x02]/q1
s/<math>/\x00/g
s/<\/math>/\x01/g
s/\\\\/\x02/g
s/\x00\([^\x01\x02]*\)\x01/<math>\1<\/math>/g
s/\x00/<math>\\begin{align}/g
s/\x01/\\end{align}<\/math>/g
s/\x02/\\\\/g' file
How I can make the following external command within ticks work with variables instead?
Or something similar?
sed -i.bak -e '10,16d;17d' $docname; (this works)
I.e., sed -i.bak -e '$line_number,$line_end_number;$last_line' $docname;
my $result =
qx/sed -i.bak -e "$line_number,${line_end_number}d;${last_line}d" $docname/;
Where the line split avoid the horizontal scroll-bar on SO; otherwise, it would be on one line.
Or, since it is not clear that there's any output to capture:
system "sed -i.back '$line_number,${line_end_number}d;${last_line}d' $docname";
Or you could split that up into arguments yourself:
system "sed", "-i.back", "$line_number,${line_end_number}d;${last_line}d", "$docname";
This tends to be safer since the shell doesn't get a chance to interfere with the interpretation of the arguments.
#args = ("command", "arg1", "arg2");
system(#args) == 0 or die "system #args failed: $?"
Furthermore on the manual:
perldoc -f system
I think you should read up on using qq for strings.
You probably want something like this:
use strict;
use warnings;
my $line_number = qq|10|;
my $line_end_number = qq|16d|;
my $last_line = qq|17d|;
my $doc_name = qq|somefile.bak|;
my $sed_command = qq|sed -i.bak -e '$line_number,$line_end_number;$last_line' $doc_name;|;
print $sed_command;
qx|$sed_command|;
In awk I can write: awk -F: 'BEGIN {OFS = FS} ...'
In Perl, what's the equivalent of FS? I'd like to write
perl -F: -lane 'BEGIN {$, = [what?]} ...'
update with an example:
echo a:b:c:d | awk -F: 'BEGIN {OFS = FS} {$2 = 42; print}'
echo a:b:c:d | perl -F: -ane 'BEGIN {$, = ":"} $F[1] = 42; print #F'
Both output a:42:c:d
I would prefer not to hard-code the : in the Perl BEGIN block, but refer to wherever the -F option saves its argument.
To sum up, what I'm looking for does not exist:
there's no variable that holds the argument for -F, and more importantly
Perl's "FS" is fundamentally a different data type (regular expression) than the "OFS" (string) -- it does not make sense to join a list of strings using a regex.
Note that the same holds true in awk: FS is a string but acts as regex:
echo a:b,c:d | awk -F'[:,]' 'BEGIN {OFS=FS} {$2=42; print}'
outputs "a[:,]42[:,]c[:,]d"
Thanks for the insight and workarounds though.
You can use perl's -s (similar to awk's -v) to pass a "FS" variable, but the split becomes manual:
echo a:b:c:d | perl -sne '
BEGIN {$, = $FS}
#F = split $FS;
$F[1] = 42;
print #F;
' -- -FS=":"
If you know the exact length of input, you could do this:
echo a:b:c:d | perl -F'(:)' -ane '$, = $F[1]; #F = #F[0,2,4,6]; $F[1] = 42; print #F'
If the input is of variable lengths, you'll need something more sophisticated than #f[0,2,4,6].
EDIT: -F seems to simply provide input to an automatic split() call, which takes a complete RE as an expression. You may be able to find something more suitable by reading the perldoc entries for split, perlre, and perlvar.
You can sort of cheat it, because perl is actually using the split function with your -F argument, and you can tell split to preserve what it splits on by including capturing parens in the regex:
$ echo a:b:c:d | perl -F'(:)' -ane 'print join("/", #F);'
a/:/b/:/c/:/d
You can see what perl's doing with some of these "magic" command-line arguments by using -MO=Deparse, like this:
$ perl -MO=Deparse -F'(:)' -ane 'print join("/", #F);'
LINE: while (defined($_ = <ARGV>)) {
our(#F) = split(/(:)/, $_, 0);
print join('/', #F);
}
-e syntax OK
You'd have to change your #F subscripts to double what they'd normally be ($F[2] = 42).
Darnit...
The best I can do is:
echo a:b:c:d | perl -ne '$v=":";#F = split("$v"); $F[1] = 42; print join("$v", #F) . "\n";'
You don't need the -F: this way, and you're only stating the colon once. I was hoping there was someway of setting variables on the command line like you can with Awk's -v switch.
For one liners, Perl is usually not as clean as Awk, but I remember using Awk before I knew of Perl and writing 1000+ line Awk scripts.
Trying things like this made people think Awk was either named after the sound someone made when they tried to decipher such a script, or stood for AWKward.
There is no input record separator in Perl. You're basically emulating awk by using the -a and -F flags. If you really don't want to hard code the value, then why not just use an environmental variable?
$ export SPLIT=":"
$ perl -F$SPLIT -lane 'BEGIN { $, = $ENV{SPLIT}; } ...'