How to append a line after a search result? - bash

So I grep for something in some file:
grep "import" test.txt | tail -1
In test.txt there is
import-one
import-two
import-three
some other stuff in the file
This will return the last search result:
import-three
Now how do I add some text -after-- import-three but before "some other stuff in the file". Basically I want to append a line but not at the end of a file but after a search result.

I understand that you want some text after each search result, which would mean after every matching line. So try
grep "import" test.txt | sed '/$/ a\Line to be added'

You can try something like this with sed
sed '/import-three/ a\
> Line to be added' t
Test:
$ sed '/import-three/ a\
> Line to be added' t
import-one
import-two
import-three
Line to be added
some other stuff in the file

One way assuming that you cannot distingish between different "import" sentences. It reverses the file with tac, then find the first match (import-three) with sed, insert a line just before it (i\) and reverse again the file.
The :a ; n ; ba is a loop to avoid processing again the /import/ match.
The command is written throught several lines because the sed insert command is very special with the syntax:
$ tac infile | sed '/import/ { i\
"some text"
:a
n
ba }
' | tac -
It yields:
import-one
import-two
import-three
"some text"
some other stuff in the file

Using ed:
ed test.txt <<END
$
?^import
a
inserted text
.
w
q
END
Meaning: go to the end of the file, search backwards for the first line beginning with import, add the new lines below (insertion ends with a "." line), save and quit

Related

How to get values in a line while looping line by line in a file (shell script)

I have a file which looks like this (file.txt)
{"key":"AJGUIGIDH568","rule":squid:111-some_random_text_here
{"key":"TJHJHJHDH568","rule":squid:111-some_random_text_here
{"key":"YUUUIGIDH566","rule":squid:111-some_random_text_here
{"key":"HJHHIGIDH568","rule":squid:111-some_random_text_here
{"key":"ATYUGUIDH556","rule":squid:111-some_random_text_here
{"key":"QfgUIGIDH568","rule":squid:111-some_random_text_here
I want to loop trough this line by line an extract the key values.
so the result should be like ,
AJGUIGIDH568
AJGUIGIDH568
YUUUIGIDH566
HJHHIGIDH568
ATYUGUIDH556
QfgUIGIDH568
So I wrote a code like this to loop line by line and extract the value between {"key":" and ","rule": because key values is in between these 2 patterns.
while read p; do
echo $p | sed -n "/{"key":"/,/","rule":,/p"
done < file.txt
But this is not working. can someone help me to figure out me this. Thanks in advance.
Your sample input is almost valid json. You could tweak it to make it valid and then extract the values with jq with something like:
sed -e 's/squid/"squid/' -e 's/$/"}/' file.txt | jq -r .key
Or, if your actual input really is valid json, then just use jq:
jq -r .key file.txt
If the "random-txt" may include double quotes, making it difficult to massage the input to make it valid json, perhaps you want something like:
awk '{print $4}' FS='"' file.txt
or
sed -n '/{"key":"\([^"]*\).*/s//\1/p' file.txt
or
while IFS=\" read open_brace key colon val _; do echo "$val"; done < file.txt
For the shown data, you can try this awk:
awk -F '"[:,]"' '{print $2}' file
AJGUIGIDH568
TJHJHJHDH568
YUUUIGIDH566
HJHHIGIDH568
ATYUGUIDH556
QfgUIGIDH568
With the give example you can simple use
cut -d'"' -f4 file.txt
Assumptions:
there may be other lines in the file so we need to focus on just the lines with "key" and "rule"
the only text between "key" and "rule" is the desired string (eg, squid never shows up between the two patterns of interest)
Adding some additional lines:
$ cat file.txt
{"key":"AJGUIGIDH568","rule":squid:111-some_random_text_here
ignore this line}
{"key":"TJHJHJHDH568","rule":squid:111-some_random_text_here
ignore this line}
{"key":"YUUUIGIDH566","rule":squid:111-some_random_text_here
ignore this line}
{"key":"HJHHIGIDH568","rule":squid:111-some_random_text_here
ignore this line}
{"key":"ATYUGUIDH556","rule":squid:111-some_random_text_here
ignore this line}
{"key":"QfgUIGIDH568","rule":squid:111-some_random_text_here
ignore this line}
One sed idea:
$ sed -nE 's/^(.*"key":")([^"]*)(","rule".*)$/\2/p' file.txt
AJGUIGIDH568
TJHJHJHDH568
YUUUIGIDH566
HJHHIGIDH568
ATYUGUIDH556
QfgUIGIDH568
Where:
-E - enable extended regex support (and capture groups without need to escape sequences)
-n - suppress printing of pattern space
^(.*"key":") - [1st capture group] everything from start of line up to and including "key":"
([^"]*) - [2nd capture group] everything that is not a double quote (")
(","rule".*)$ - [3rd capture group] everything from ",rule" to end of line
\2/p - replace the line with the contents of the 2nd capture group and print

Replace one string with the content pulled from other file

I have an TARGET.md file, I'm looking for a string and I want to replace it with the content of other md file, I have tried many combinations but it seems like the newline in the files are the ones sed is not liking, I just need to do this using pure bash(it doesn't have to be sed) because this is how the whole script is running:
This works:
local search="##### Header"
local replace="##### Header\\
\\
Line 1\\
Line 2\\
Line 3\\
Line 4"
sed -i '' -e "s/${search}/${replace}/" TARGET.md
But this won't:
file1.md content:
##### Header
Line 1
Line 2
Line 3
Line 4
Script:
local search="##### Header"
local replace=$(curl "path/to/file/in/other/place/file1.md")
sed -i '' -e "s/${search}/${replace}/" TARGET.md
NOTE: I don't have the file1.md in the same place, I'm doing a curl to get the raw content from it, this is why the replace is in a variable.
I'm assuming the concept is possible but my sed syntax is wrong knowing sed can handle newlines out of the box, but not sure what is the proper way to do this.
I've been searching for some days now, any help, tip or guide is appreciated!
You are using the wrong tool. sed is a line editor at heart. While you can repeatedly append to pattern space in some instances, awk with getline provides a more flexible solution. For example with your file1.md:
##### Header
Line 1
Line 2
Line 3
Line 4
and your TARGET.md as:
##### Unreleased
my dog
has fleas
The to replace "##### Unreleased" with the content of file1.md, you can do:
awk -v replace="file1.md" -v search="##### Unreleased" '
$0 == search {while (getline line < replace ) { print line }; next }
{ print }
' TARGET.md
Above you have your replace and search as with sed, but instead of using the line-editor, you use awk to locate the line containing search and the read all lines from replace using getline`. The second rule just prints all other lines as is.
Example Use/Output
In the directory containing each file, you can simply select-copy the above and middle-mouse paste into the terminal to test:
$ awk -v replace="file1.md" -v search="##### Unreleased" '
> $0 == search {while (getline line < replace ) { print line }; next }
> { print }
> ' TARGET.md
##### Header
Line 1
Line 2
Line 3
Line 4
my dog
has fleas
Look things over and let me know if you have further questions.
Taking TARGET.md file from David's answer:
cat TARGET.md
##### Unreleased
my dog
has fleas
You can run sed with r command like this:
search="##### Unreleased"
sed -e "/$search/{r file1.md" -e ';d;}' TARGET.md
##### Header
Line 1
Line 2
Line 3
Line 4
my dog
has fleas

sed/awk between two patterns in a file: pattern 1 set by a variable from lines of a second file; pattern 2 designated by a specified charcacter

I have two files. One file contains a pattern that I want to match in a second file. I want to use that pattern to print between that pattern (included) up to a specified character (not included) and then concatenate into a single output file.
For instance,
File_1:
a
c
d
and File_2:
>a
MEEL
>b
MLPK
>c
MEHL
>d
MLWL
>e
MTNH
I have been using variations of this loop:
while read $id;
do
sed -n "/>$id/,/>/{//!p;}" File_2;
done < File_1
hoping to obtain something like the following output:
>a
MEEL
>c
MEHL
>d
MLWL
But have had no such luck. I have played around with grep/fgrep awk and sed and between the three cannot seem to get the right (or any output). Would someone kindly point me in the right direction?
Try:
$ awk -F'>' 'FNR==NR{a[$1]; next} NF==2{f=$2 in a} f' file1 file2
>a
MEEL
>c
MEHL
>d
MLWL
How it works
-F'>'
This sets the field separator to >.
FNR==NR{a[$1]; next}
While reading in the first file, this creates a key in array a for every line in file file.
NF==2{f=$2 in a}
For every line in file 2 that has two fields, this sets variable f to true if the second field is a key in a or false if it is not.
f
If f is true, print the line.
A plain (GNU) sed solution. Files are read only once. It is assumed that characters in File_1 needn't to be quoted in sed expression.
pat=$(sed ':a; $!{N;ba;}; y/\n/|/' File_1)
sed -E -n ":a; /^>($pat)/{:b; p; n; /^>/ba; bb}" File_2
Explanation:
The first call to sed generates a regular expression to be used in the second call to sed and stores it in the variable pat. The aim is to avoid reading repeatedly the entire File_2 for each line of File_1. It just "slurps" the File_1 and replaces new-line characters with | characters. So the sample File_1 becomes a string with the value a|c|d. The regular expression a|c|d matches if at least one of the alternatives (a, b, c for this example) matches (this is a GNU sed extension).
The second sed expression, ":a; /^>($pat)/{:b; p; n; /^>/ba; bb}", could be converted to pseudo code like this:
begin:
read next line (from File_2) or quit on end-of-file
label_a:
if line begins with `>` followed by one of the alternatives in `pat` then
label_b:
print the line
read next line (from File_2) or quit on end-of-file
if line begins with `>` goto label_a else goto label_b
else goto begin
Let me try to explain why your approach does not work well:
You need to say while read id instead of while read $id.
The sed command />$id/,/>/{//!p;} will exclude the lines which start
with >.
Then you might want to say something like:
while read id; do
sed -n "/^>$id/{N;p}" File_2
done < File_1
Output:
>a
MEEL
>c
MEHL
>d
MLWL
But the code above is inefficient because it reads File_2 as many times as the count of the id's in File_1.
Please try the elegant solution by John1024 instead.
If ed is available, and since the shell is involve.
#!/usr/bin/env bash
mapfile -t to_match < file1.txt
ed -s file2.txt <<-EOF
g/\(^>[${to_match[*]}]\)/;/^>/-1p
q
EOF
It will only run ed once and not every line that has the pattern, that matches from file1. Like say if you have a to z from file1,ed will not run 26 times.
Requires bash4+ because of mapfile.
How it works
mapfile -t to_match < file1.txt
Saves the entry/value from file1 in an array named to_match
ed -s file2.txt point ed to file2 with the -s flag which means don't print info about the file, same info you get with wc file
<<-EOF A here document, shell syntax.
g/\(^>[${to_match[*]}]\)/;/^>/-1p
g means search the whole file aka global.
( ) capture group, it needs escaping because ed only supports BRE, basic regular expression.
^> If line starts with a > the ^ is an anchor which means the start.
[ ] is a bracket expression match whatever is inside of it, in this case the value of the array "${to_match[*]}"
; Include the next address/pattern
/^>/ Match a leading >
-1 go back one line after the pattern match.
p print whatever was matched by the pattern.
q quit ed

How do I insert a newline/linebreak after a line using sed

It took me a while to figure out how to do this, so posting in case anyone else is looking for the same.
For adding a newline after a pattern, you can also say:
sed '/pattern/{G;}' filename
Quoting GNU sed manual:
G
Append a newline to the contents of the pattern space, and then append the contents of the hold space to that of the pattern space.
EDIT:
Incidentally, this happens to be covered in sed one liners:
# insert a blank line below every line which matches "regex"
sed '/regex/G'
This sed command:
sed -i '' '/pid = run/ a\
\
' file.txt
Finds the line with: pid = run
file.txt before
; Note: the default prefix is /usr/local/var
; Default Value: none
;pid = run/php-fpm.pid
; Error log file
and adds a linebreak after that line inside file.txt
file.txt after
; Note: the default prefix is /usr/local/var
; Default Value: none
;pid = run/php-fpm.pid
; Error log file
Or if you want to add text and a linebreak:
sed -i '/pid = run/ a\
new line of text\
' file.txt
file.txt after
; Note: the default prefix is /usr/local/var
; Default Value: none
;pid = run/php-fpm.pid
new line of text
; Error log file
A simple substitution works well:
sed 's/pattern.*$/&\n/'
Example :
$ printf "Hi\nBye\n" | sed 's/H.*$/&\nJohn/'
Hi
John
Bye
To be standard compliant, replace \n by backslash newline :
$ printf "Hi\nBye\n" | sed 's/H.*$/&\
> John/'
Hi
John
Bye
sed '/pattern/a\\r' file name
It will add a return after the pattern while g will replace the pattern with a blank line.
If a new line (blank) has to be added at end of the file use this:
sed '$a\\r' file name
Another possibility, e.g. if You don't have an empty hold register, could be:
sed '/pattern/{p;s/.*//}' file
Explanation:
/pattern/{...} = apply sequence of commands, if line with pattern found,
p = print the current line,
; = separator between commands,
s/.*// = replace anything with nothing in the pattern register,
then automatically print the empty pattern register as additional line)
The easiest option -->
sed 'i\
' filename

Delete lines before and after a match in bash (with sed or awk)?

I'm trying to delete two lines either side of a pattern match from a file full of transactions. Ie. find the match then delete two lines before it, then delete two lines after it and then delete the match. The write this back to the original file.
So the input data is
D28/10/2011
T-3.48
PINITIAL BALANCE
M
^
and my pattern is
sed -i '/PINITIAL BALANCE/,+2d' test.txt
However this is only deleting two lines after the pattern match and then deleting the pattern match. I can't work out any logical way to delete all 5 lines of data from the original file using sed.
an awk one-liner may do the job:
awk '/PINITIAL BALANCE/{for(x=NR-2;x<=NR+2;x++)d[x];}{a[NR]=$0}END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' file
test:
kent$ cat file
######
foo
D28/10/2011
T-3.48
PINITIAL BALANCE
M
x
bar
######
this line will be kept
here
comes
PINITIAL BALANCE
again
blah
this line will be kept too
########
kent$ awk '/PINITIAL BALANCE/{for(x=NR-2;x<=NR+2;x++)d[x];}{a[NR]=$0}END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' file
######
foo
bar
######
this line will be kept
this line will be kept too
########
add some explanation
awk '/PINITIAL BALANCE/{for(x=NR-2;x<=NR+2;x++)d[x];} #if match found, add the line and +- 2 lines' line number in an array "d"
{a[NR]=$0} # save all lines in an array with line number as index
END{for(i=1;i<=NR;i++)if(!(i in d))print a[i]}' #finally print only those index not in array "d"
file # your input file
sed will do it:
sed '/\n/!N;/\n.*\n/!N;/\n.*\n.*PINITIAL BALANCE/{$d;N;N;d};P;D'
It works this way:
if sed has only one string in pattern space it joins another one
if there are only two it joins the third one
if it does natch to pattern LINE + LINE + LINE with BALANCE it joins two following strings, deletes them and goes at the beginning
if not, it prints the first string from pattern and deletes it and goes at the beginning without swiping the pattern space
To prevent the appearance of pattern on the first string you should modify the script:
sed '1{/PINITIAL BALANCE/{N;N;d}};/\n/!N;/\n.*\n/!N;/\n.*\n.*PINITIAL BALANCE/{$d;N;N;d};P;D'
However, it fails in case you have another PINITIAL BALANCE in string which are going to be deleted. However, other solutions fails too =)
For such a task, I would probably reach for a more advanced tool like Perl:
perl -ne 'push #x, $_;
if (#x > 4) {
if ($x[2] =~ /PINITIAL BALANCE/) { undef #x }
else { print shift #x }
}
END { print #x }' input-file > output-file
This will remove 5 lines from the input file. These lines will be the 2 lines before the match, the matched line, and the two lines afterwards. You can change the total number of lines being removed modifying #x > 4 (this removes 5 lines) and the line being matched modifying $x[2] (this makes the match on the third line to be removed and so removes the two lines before the match).
A more simple and easy to understand solution might be:
awk '/PINITIAL BALANCE/ {print NR-2 "," NR+2 "d"}' input_filename \
| sed -f - input_filename > output_filename
awk is used to make a sed-script that deletes the lines in question and the result is written on the output_filename.
This uses two processes which might be less efficient than the other answers.
This might work for you (GNU sed):
sed ':a;$q;N;s/\n/&/2;Ta;/\nPINITIAL BALANCE$/!{P;D};$q;N;$q;N;d' file
save this code into a file grep.sed
H
s:.*::
x
s:^\n::
:r
/PINITIAL BALANCE/ {
N
N
d
}
/.*\n.*\n/ {
P
D
}
x
d
and run a command like this:
`sed -i -f grep.sed FILE`
You can use it so either:
sed -i 'H;s:.*::;x;s:^\n::;:r;/PINITIAL BALANCE/{N;N;d;};/.*\n.*\n/{P;D;};x;d' FILE

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