I do not understand the command grouping in sed scripts. We use curly braces to group commands. I found some information in the first answer to the following question: Using multiple sed commands. But I still do not understand this properly. Could someone please explain this to me?
If you use
/Number/ s/N/n/;s/r//
Then rs will be removed on all lines, not only those containing Number. But, if you use
/Number/{s/N/n/;s/r//}
then rs will be removed only from lines containing Number.
Related
I am attempting to add a parameter based on an additional list 'list2.txt' that I have created and I am not quite sure how to implement it.
My running code
while read i
do
sed "s/Pie/$i/g" old_script.sh > new_script.$i.sh
sbatch new_script.$i.sh
done<list.txt
But I want to add the following condition with based on a new list... and I am not quite sure how to implement it into my working script
sed "s/Apple/__/g"
sed allows several ways to supply multiple commands. You can give them individually with -e or just write them into a single script string.
GNU sed allows commands on the same line to be separated with semicolons, and is genrally what you will find, but if you don't have that version you can use embedded newlines. As long as it's quoted it will work fine.
sed "s/Pie/$i/g; s/Apple/__/g;" old_script.sh # GNU specific but common
or
sed "
s/Pie/$i/g
s/Apple/__/g
" old_script.sh # general, should always work.
These are both valid.
I have a parsed content similar to this as a output from JSON.sh.
["/home/ukrishnan/projects/test.yml","LOG_DRIVER"] "syslog"
["/home/ukrishnan/projects/test.yml","IMAGE"] "mysql:5.6"
["/home/ukrishnan/projects/test.yml"] {"LOG_DRIVER":"syslog","IMAGE":"mysql:5.6"}
["/home/ukrishnan/projects/mysql/app.xml","ENV_ACCOUNT_BRIDGE_ENDPOINT"] "/u01/src/test/sample.txt"
["/home/ukrishnan/projects/mysql/app.xml"] {"ENV_ACCOUNT_BRIDGE_ENDPOINT":"/u01/src/test/sample.txt"}
[] {"/home/ukrishnan/projects/test.yml":{"LOG_DRIVER":"syslog","IMAGE":"mysql:5.6"},"/home/ukrishnan/projects/mysql/app.xml":{"ENV_ACCOUNT_BRIDGE_ENDPOINT":"/u01/src/test/sample.txt"}}
So, I just wanted to take the values, similar to the Line 1,2 and 4. And need to parse, for example in the first line, "/home/ukrishnan/projects/test.yml","LOG_DRIVER","syslog" for all the lines with similar format. Please help as I'm completely a newbie to grep or awk.
Edit:
Sorry, if this is two broad. Here is what I tried.
By using, grep -v "{\|}" returns,
["/home/ukrishnan/projects/test.yml","LOG_DRIVER"] "syslog"
["/home/ukrishnan/projects/test.yml","IMAGE"] "mysql:5.6"
["/home/ukrishnan/projects/mysql/app.xml","ENV_ACCOUNT_BRIDGE_ENDPOINT"] "/u01/src/test/sample.txt"
If someone helps me with also grabbing values within double quotes in a single grep, that would be great.
this one-liner works for your example:
awk '$NF~/^[^{]/&&sub(/^\[/,"")+sub(/\]\s*/,",")' file
It gives:
"/home/ukrishnan/projects/test.yml","LOG_DRIVER","syslog"
"/home/ukrishnan/projects/test.yml","IMAGE","mysql:5.6"
"/home/ukrishnan/projects/mysql/app.xml","ENV_ACCOUNT_BRIDGE_ENDPOINT","/u01/src/test/sample.txt"
There is a way to remove from a file all rows wrapped between /* and */ using a bash script?
I use percona to generate a sql script to syncronize two databases, a development one to a production one. Percona generates a well formatted SQL script but full of comments which make increase file size. So, just to make easier upload operation I'd prefer to remove all the unnecessary.
EDIT ON January 10th
I solved with this code:
sed -r ':a; s%(.*)/\*.*\*/%\1%; ta; /\/\*/ !b; N; ba' <FILE_TO_CLEAN>
thanks all
Using sed:
sed '/\/\*.*\*\// d; /\/\*/,/\*\// d' file
The command d tells sed to delete patterns matching the preceeding expression. The first expression /\/\*.*\*\// matches one-line comments, the second one /\/\*/,/\*\// comments that range multiple lines (this is implied by the ,).
I don't know if this works 100%, but as far as I tried, it did the job.
-Try this script- it should help removing the comments, since are the same as C++ Here you can see another sed example to remove HTML comments
(Sorry for the confusion. Previous $ sign occurred when I tried to simplify the actual problem. Thanks for correcting the question)
I wanted to split a directory name on underscores (ex: dir_to_split="my_test_dir") like this:
my_dir=($dir_to_split)
var=$(echo $my_dir | awk -F"_" '{print $1,$2,$3}')
set -- $var
splited_1=$1
splited_2=$2
splited_3=$3
now using these splited_x is causing me errors. ex.
myprograme $splited_1 $splited_2 $splited_3
Can anyone please help me with this ? Thank you....
(Rewritten after updated question.)
What kind of errors do you get? I find it useful to add set -x to the top of my shell scripts when debugging, this lets the shell print all commands it executes so you can pinpoint the line where problems begin.
Are you sure that $dir_to_split is actually set? Does it contain spaces or tabs? Does it contain two underscores? I don't see any other problems right now.
There are in-shell methods of splitting a variable such as:
dir="my_test_dir"
OIFS="$IFS"
IFS="-"
set --
IFS="$OIFS"
See also this SO question.
I am writing a shell (bash) script and I'm trying to figure out an easy way to accomplish a simple task.
I have some string in a variable.
I don't know if this is relevant, but it can contain spaces, newlines, because actually this string is the content of a whole text file.
I want to replace the last occurence of a certain substring with something else.
Perhaps I could use a regexp for that, but there are two moments that confuse me:
I need to match from the end, not from the start
the substring that I want to scan for is fixed, not variable.
for truncating at the start: ${var#pattern}
truncating at the end ${var%pattern}
${var/pattern/repl} for general replacement
the patterns are 'filename' style expansion, and the last one can be prefixed with # or % to match only at the start or end (respectively)
it's all in the (long) bash manpage. check the "Parameter Expansion" chapter.
amn expression like this
s/match string here$/new string/
should do the trick - s is for sustitute, / break up the command, and the $ is the end of line marker. You can try this in vi to see if it does what you need.
I would look up the man pages for awk or sed.
Javier's answer is shell specific and won't work in all shells.
The sed answers that MrTelly and epochwolf alluded to are incomplete and should look something like this:
MyString="stuff ttto be edittted"
NewString=`echo $MyString | sed -e 's/\(.*\)ttt\(.*\)/\1xxx\2/'`
The reason this works without having to use the $ to mark the end is that the first '.*' is greedy and will attempt to gather up as much as possible while allowing the rest of the regular expression to be true.
This sed command should work fine in any shell context used.
Usually when I get stuck with Sed I use this page,
http://sed.sourceforge.net/sed1line.txt