sed is a command-line stream editor for filtering and transforming text.

learn more… | top users | synonyms

12
votes
4answers
10k views

sed on OSX insert at a certain line

So I've been using 'sed' on linux for a while, but have had a bit of difficulty trying to use it on OSX since 'POSIX sed' and 'GNU sed' have so many little differences. Currently I'm struggling with ...
12
votes
4answers
25k views

How to write text into the first line of a file?

I've been looking around sed command to add text into a file in a specific line. This works adding text after line 1: sed '1 a\ But I want to add it before line 1. It would be: sed '0 a\ but I ...
12
votes
3answers
28k views

Extracting a regex matched with 'sed' without printing the surrounding characters

To all the 'sed' doctors out there: How can you get 'sed' to extract a regular expression it has matched in a line? In other words words, I want just the string corresponding to the regular ...
12
votes
1answer
18k views

Delete specific line number(s) from a text file using sed?

I want to delete one or more specific line numbers from a file. How would I do this using sed?
12
votes
3answers
9k views

Zero-fill numbers to 2 digits with sed

Input: 201103 1 /mnt/hdd/PUB/SOMETHING 201102 7 /mnt/hdd/PUB/SOMETH ING 201103 11 /mnt/hdd/PUB/SO METHING 201104 3 /mnt/hdd/PUB/SOMET HING 201106 1 /mnt/hdd/PUB/SOMETHI NG Desired output: 201103 ...
12
votes
1answer
7k views

Removing leading zeros from DATE

I made an alias of the date command to display date in the following format: 2013.06.14.12.10.02 using this command: alias date = date +"%Y.%m.%d.%H.%M.%S" Everything works great, except I ...
11
votes
3answers
10k views

How do I replace the last occurrence of a character in a string using sed?

How do I replace only the last occurrence of "-" in a string with a space using sed? For example: echo $MASTER_DISK_RELEASE swp-RedHat-Linux-OS-5.5.0.0-03 but I want to get the following output ( ...
11
votes
2answers
25k views

How to replace a string with a string containing slash with sed?

i am looking for a way to replace a string in a file with a string that contains a slash by using sed. connect="192.168.100.61/foo" srcText="foo.bar=XPLACEHOLDERX" echo $srcText | sed ...
11
votes
5answers
17k views

Delete range of lines above pattern with sed (or awk)

I have the following code that will remove lines with the pattern banana and 2 lines after it: sed '/banana/I,+2 d' file So far, so good! But I need it to remove 2 lines before banana, but I can't ...
11
votes
4answers
12k views

How to insert a new line after every second line?

sed/bash/wharever :D INPUT: sadf asdf yxcv cxv eqrt asdf OUTPUT: sadf asdf yxcv cxv eqrt asdf
11
votes
5answers
27k views

Remove multiple lines after a pattern match but only after pattern match

I am trying to remove all instances of a pattern match from a file if it matches a pattern. If there is a match, the (complete) line with the matching pattern and the next line get removed. The next ...
11
votes
4answers
24k views

How to extract logs between two time stamps

I want to extract all logs between two timestamps. Some lines may not have the timestamp, but I want those lines also. In short, I want every line that falls under two time stamps. My log structure ...
11
votes
4answers
258 views

Comment all lines from last commented line to line with 'foo'

Consider a text file users.txt: #alice #bob charlie dotan eric I need to comment everything from (exclusive) the last commented line until (inclusive) dotan. This is the result: #alice #bob ...
11
votes
2answers
4k views

Using sed to color the output from a command on solaris

I have a ksh script that must work on both linux and solaris. I'm trying to color the output of specific commands. It works on linux (specifically RHEL6), but not on solaris (SunOS 5.10). Command ...
10
votes
9answers
2k views

How can I print the longest number in a string?

I am looking for a method to print the longest number in a string. E.g.: If I have the string 212334123434test233 how can I print 212334123434 ? Note: I am looking for the longest continuous ...
10
votes
4answers
2k views

Output part of each line to a separate file

I have a file like this: a AGTACTTCCAGGAACGGTGCACTCTCC b ATGGATTTTTGGAGCAGGGAGATGGAATAGGAGCATGCTCCAT c ATATTAAATGGATTTTTGGAGCAGGGAGATGGAATAGGAGCATGCTCCATCCACTCCACAC d ...
10
votes
12answers
3k views

What's a good way to filter a text file to remove empty lines?

I have a .csv file (on a mac) that has a bunch of empty lines, e.g.: "1", "2", "lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum ...
10
votes
6answers
699 views

Remove lines from a file depending on lines found in another file

File file1.txt contains lines like: /api/purchase/<hash>/index.html For example: /api/purchase/12ab09f46/index.html File file2.csv contains lines like: <hash>,timestamp,ip_address ...
10
votes
3answers
997 views

What does sed -i '1d' do?

I understand that sed is a command to manipulate text file. From my Googling, it seems -i means perform the operation on the file itself, is this correct? What about '1d'?
10
votes
5answers
7k views

How to remove multiple blank lines from a file?

I have some text-files I use to take notes in - just plain text, usually just using cat >> file. Occasionally I use a blank line or two (just return - the new-line character) to specify a new ...
10
votes
6answers
50k views

Using sed to find and replace complex string (preferrably with regex)

I have a file with the following contents: <username><![CDATA[name]]></username> <password><![CDATA[password]]></password> ...
10
votes
1answer
13k views

How to replace a left parenthesis with sed?

I have to replace ( with some character in my file, and I can't do it. \( is used for grouping in sed and when I used \\( with sed, it treated it as \( character not as just (. It seems like a tricky ...
10
votes
5answers
2k views

Case matching pattern replacement with sed

I have a source code spread across several files. It has a pattern abcdef which I need to replace with pqrstuvxyz. The pattern could be Abcdef (Sentence Case) then it needs to be replaced with ...
10
votes
3answers
13k views

How to sed only that lines that contains given string?

INPUT: Select ASDF 325 sdfg sdflk lk Select TRG 46sdg rasdftz fsgs 45 Select ASDF 6ffg sdfg 4456 sdrg OUTPUT: Select ASDF 325 XXXX sdflk lk Select TRG 46sdg rasdftz fsgs 45 Select ASDF 6ffg XXXX ...
10
votes
2answers
435 views

Reindexing a large CSV file

I went through the answers in this helpful thread, but my problem seems to be different enough that I can't think of good answer (at least with sed). I have a large CSV file (200+ GB) with rows that ...
10
votes
1answer
292 views

How does this sed command work?

I've come across this solution for printing a specific line from a text file: sed '123!d;q' file Why doesn't sed quit after the first line of input in this case?
10
votes
3answers
8k views

Diff, show modified line from right file only

I have file a and b and I would like to output lines of b that changed since it was cloned from a. Just the modified lines, no surrounding context, no diff offset marks. How can I do that using shell ...
10
votes
8answers
621 views

sed in-place line deletion on full filesystem?

Due to an application bug as yet undiagnosed, I have several hundred servers with a full disk. There is one file that has been filled up with duplicate lines—not a log file, but a user environment ...
10
votes
3answers
4k views

How can I instruct BSD sed to interpret escape sequences like \n and \t?

I have a sed replacement command that I would like to be compatible with BSD sed as well as GNU sed. Extended regular expressions are not an issue as I do not need them in this case. My primary ...
10
votes
2answers
35k views

Removing all spaces, tabs, newlines, etc from a variable?

This is the error I am getting and it's failing because of a variable whose value is supposed to be 2 (I am getting this using a select * from tabel). I am getting spaces in that variable. + 0 != ...
10
votes
2answers
1k views

grep: display filename once, then display context with line numbers

Our source code has error codes scattered throughout. Finding them is easy with grep, but I'd like a bash function find_code that I can execute (eg. find_code ####) which will provide output along ...
10
votes
4answers
291 views

Script to extract selected entries from a bibtex file

I have a large bibtex file with many entries where each entry has the general structure @ARTICLE{AuthorYear, item = {...}, item = {...}, item = {...}, etc } (in some cases ARTICLE might be a ...
10
votes
1answer
362 views

regarding portable sed -e… d b or ! b?

In this edit Stéphane Chazelas POSIXifies (again) my sed formatting by inserting an -expression break and another -expression statement. Now, I might just ask him why in the comments, I suppose, but ...
9
votes
8answers
11k views

Can sed remove 'double' newline characters?

I have a document with a lot of empty lines. How can I remove them when there are 2 or more together. I tried sed "s/\n\n//" file but it didn't work. No error.
9
votes
7answers
621 views

Swapping an unlimited number of columns

I have a file with columns. See below for an example: a b c ... z 1 2 3 ... 26 I'd like to swap all columns where the 1st becomes the last, the second becomes the one before last...etc.. z y x ...
9
votes
6answers
45k views

How to use a shell command to only show the first column and last column in a text file?

I need some help to figure out how to use the sed command to only show the first column and last column in a text file. Here is what I have so far for column 1: cat logfile | sed 's/\|/ /'|awk ...
9
votes
5answers
1k views

Merge two files line by line with the delimiter triple pipe symbol “|||”

I have two parallel files with the same number of lines in two languages and plan to merge these two files line by line with the delimiter |||. E.g., the two files are as follows: File A: 1Mo 1,1 I ...
9
votes
7answers
14k views

Sed — Replace first k instances of a word in the file

I want to replace only the first k instances of a word. How can I do this? Eg. Say file foo.txt contains 100 instances occurrences of word 'linux' . I need to replace first 50 occurrences only.
9
votes
4answers
33k views

How to use Sed to replace all characters before colon?

How do I replace the following string hd_ma_prod_customer_ro:*:123456789:john.doe with john.doe Basically I need to look for the last colon (:) and delete everything before and including it.
9
votes
2answers
4k views

How to remove multiple lines per occurrence in a file?

Say I have this 857835 line file, containing stuff like this: a1 rubbish1 rubbish2 rubbish3 rubbish4 a1 rubbish5 rubbish6 rubbish7 rubbish8 And I wish to remove all occurences of a1 and the next ...
9
votes
5answers
17k views

Simple sed replacement of tabs mysteriously failing

This ought to be really simple, but for some reason it is not working: sed -i.bak -E 's/\t/ /' file.txt Instead of replacing tab characters, it's replacing t characters. I've tried every ...
9
votes
4answers
9k views

How to embed a shell command into a sed expression?

I have a text file with the following format: keyword value keyword value ... Where keyword is a single word and value is everything else until the end of line. I want to read the file from a shell ...
9
votes
3answers
3k views

Substituting strings in a very large file

I have a very long series of urls with no separating character, in the same format as below: http://example.comhttp://example.nethttp://example.orghttp://etc... I want each URL to be on a new line. ...
9
votes
2answers
6k views

sed one-liner to delete any line that does not contain lowercase letters

So, basically THIS LINE WOULD BE DELETED and (THIS LINE WOULD ALSO BE DELETED) but Indeed, THIS LINE WOULD NOT
9
votes
5answers
4k views

How to delete line if longer than XY?

How can i delete a line if it is longer than e.g.: 2048 chars?
9
votes
5answers
8k views

Efficient in-place header removing for large files using sed?

The commands below may takes minutes depends on the file size. Is there any more effient method? sed -i 1d large_file
9
votes
6answers
41k views

Can sed replace new line characters?

Is there an issue with sed and new line character? I have a file test.txt with the following contents aaaaa bbbbb ccccc ddddd The following does not work: sed -r -i 's/\n/,/g' test.txt ...
9
votes
3answers
10k views

How to sed a range of lines?

I have this: sed -i '/^$/d' temp_spec.rb which is stripping blank lines and works well. How can I make it only do this for lines 5-999 (or ideally 5 to end-of-file). I tried: sed -n5,999 -i ...
9
votes
2answers
15k views

How can I get my sed command to make permanent changes to a file?

Is this possible? I read somewhere that the following command would do it: sed -e [command] [file] but it appeared to do the same thing as just sed [command] [file] (it did not save the ...
9
votes
4answers
8k views

Concatenate lines by first column by awk or sed

How can I use awk in the following situation? I want to concatenate lines that start with the same column. Only the first column is kept after the join (in this case aaa, www, hhh). The file may be ...