Here I want to delete the first character of file of certain lines. For example:
>cat file1.txt
10081551
10081599
10082234
10082259
20081134
20081159
30082232
10087721
From 3rd line to 7th line delete the first character sed command or any else and output will be:
>cat file1.txt
10081551
10081599
0082234
0082259
0081134
0081159
0082232
10087721
sed -i '3,7s/.//' file1.txt
sed -i.bak '3,7s/.//' file1.txt # to keep backup
From 3rd to 7th line, replace the first character with nothing.
This is simple in either sed:
sed -i '3,7 s/^.//'
or Perl:
perl -i -pe 's/^.// if $. >= 3 && $. <= 7'
The sed program can do this with:
pax$ sed '3,7s/.//' file1.txt
10081551
10081599
0082234
0082259
0081134
0081159
0082232
10087721
substituting the first character on the line that matches . (which is the first character on the line).
I'll also provide an awk solution. It's a little more complex but it's worth learning since it allows for much more complex operations than sed.
pax$ awk 'NR>=3&&NR<=7{sub("^.","",$0)}{print}' file1.txt
10081551
10081599
0082234
0082259
0081134
0081159
0082232
10087721
For your 2nd question:
if the ending quote is on the last line of the file:
sed '$i\
/home/neeraj/yocto/poky/meta-ti \\
' text
to match the end of the continued lines (this one feels fragile)
sed '
/BBLAYERS.*"/ {
:a
/\\$/ {N; ba}
s#"$#/home/neeraj/yocto/poky/meta-ti \\\n"#
}
' text
Another variation of the awk
awk 'NR~/^[3-7]$/{sub(".","")}1' file
10081551
10081599
0082234
0082259
0081134
0081159
0082232
10087721
Related
I would like to match all lines from a file containing a word, and take all lines under until coming two two newline characters in a row.
I have the following sed code to cut and paste specific lines, but not subsequent lines:
sed 's|.*|/\\<&\\>/{w results\nd}|' teststring | sed -file.bak -f - testfile
How could I modify this to take all subsequent lines?
For example, say I wanted to match lines with 'dog', the following should take the first 3 lines of the 5:
The best kind of an animal is a dog, for sure
-man's best friend
-related to wolves
Racoons are not cute
Is there a way to do this?
This should do:
awk '/dog/ {f=1} /^$/ {f=0} f {print > "new"} !f {print > "tmp"}' file && mv tmp file
It will set f to true if word dog is found, then if a blank line is found set f to false.
If f is true, print to new file.
If f is false, print to tmp file.
Copy tmp file to original file
Edit: Can be shorten some:
awk '/dog/ {f=1} /^$/ {f=0} {print > (f?"new":"tmp")}' file && mv tmp file
Edit2: as requested add space for every section in the new file:
awk '/dog/ {f=1;print ""> "new"} /^$/ {f=0} {print > (f?"new":"tmp")}' file && mv tmp file
If the original files does contains tabs or spaces instead of just a blank line after each dog section, change from /^$/ to /^[ \t]*$/
This might work for you (GNU sed):
sed 's|.*|/\\<&\\>/ba|' stringFile |
sed -f - -e 'b;:a;w resultFile' -e 'n;/^$/!ba' file
Build a set of regexps from the stringFile and send matches to :a. Then write the matched line and any further lines until an empty line (or end of file) to the resultFile.
N.B. The results could be sent directly to resultFile,using:
sed 's#.*#/\\<&\\>/ba#' stringFile |
sed -nf - -e 'b;:a;p;n;/^$/!ba' file > resultFile
To cut the matches from the original file use:
sed 's|.*|/\\<&\\>/ba|' stringFile |
sed -f - -e 'b;:a;N;/\n\s*$/!ba;w resultFile' -e 's/.*//p;d' file
Is this what you're trying to do?
$ awk -v RS= '/dog/' file
The best kind of an animal is a dog, for sure
-man's best friend
-related to wolves
Could you please try following.
awk '/dog/{count="";found=1} found && ++count<4' Input_file > temp && mv temp Input_file
I have file that contains below information
$ cat test.txt
Studentename:Ram
rollno:12
subjects:6
Highest:95
Lowest:65
Studentename:Krish
rollno:13
subjects:6
Highest:90
Lowest:45
Studentename:Sam
rollno:14
subjects:6
Highest:75
Lowest:65
I am trying place info of single student in single.
i.e My output should be
Studentename:Ram rollno:12 subjects:6 Highest:95 Lowest:65
Studentename:Krish rollno:13 subjects:6 Highest:90 Lowest:45
Studentename:Sam rollno:14 subjects:6 Highest:75 Lowest:65.
Below is the command I wrote
cat test.txt | tr "\n" " " | sed 's/Lowest:[0-9]\+/Lowest:[0:9]\n/g'
Above command is breaking line at regex Lowest:[0-9] but it doesn't print the pattern. Instead it is printing Lowest:[0-9].
Please help
Try:
$ sed '/^Studente/{:a; N; /Lowest/!ba; s/\n/ /g}' test.txt
Studentename:Ram rollno:12 subjects:6 Highest:95 Lowest:65
Studentename:Krish rollno:13 subjects:6 Highest:90 Lowest:45
Studentename:Sam rollno:14 subjects:6 Highest:75 Lowest:65
How it works
/^Studente/{...} tells sed to perform the commands inside the curly braces only on lines that start with Studente. Those commands are:
:a
This defines a label a.
N
This reads in the next line and appends it to the pattern space.
/Lowest/!ba
If the current pattern space does not contain Lowest, this tells sed to branch back to label a.
In more detail, /Lowest/ is true if the line contains Lowest. In sed, ! is negation so /Lowest/! is true if the line does not containLowest. Inba, thebstands for the branch command anda` is the label to branch to.
s/\n/ /g
This tells sed to replace all newlines with spaces.
Try this using awk :
awk '{if ($1 !~ /^Lowest/) {printf "%s ", $0} else {print}}' file.txt
Or shorter but more obfuscated :
awk '$1!~/^Lowest/{printf"%s ",$0;next}1' file.txt
Or correcting your command :
tr "\n" " " < file.txt | sed 's/Lowest:[0-9]\+/&\n/g'
Explanation: & is whats matched in the left part of substitution
Another possible GNU sed that doesn't assume Lowest is the last item:
sed ':a; N; /\nStudent/{P; D}; s/\n/ /; ba' test.txt
This might work for you (GNU sed):
sed '/^Studentename:/{:a;x;s/\n/ /gp;d};H;$ba;d' file
Use the hold space to gather up the fields and then remove the newlines to produce a record.
I want to add a text to the end of the first line of a file using a bash script.
The file is /etc/cmdline.txt which does not allow line breaks and needs new commands seperated by a blank, so text i want to add realy needs to be in first line.
What i got so far is:
line=' bcm2708.w1_gpio_pin=20'
file=/boot/cmdline.txt
if ! grep -q -x -F -e "$line" <"$file"; then
printf '%s' "$line\n" >>"$file"
fi
But that appends the text after the line break of the first line, so the result is wrong.
I either need to trim the file contend, add my text and a line feed or somehow just add it to first line of file not touching the rest somehow, but my knowledge of bash scripts is not good enough to find a solution here, and all the examples i find online add beginning/end of every line in a file, not just the first line.
This sed command will add 123 to end of first line of your file.
sed ' 1 s/.*/&123/' yourfile.txt
also
sed '1 s/$/ 123/' yourfile.txt
For appending result to the same file you have to use -i switch :
sed -i ' 1 s/.*/&123/' yourfile.txt
This is a solution to add "ok" at the first line on /etc/passwd, I think you can use this in your script with a little bit of 'tuning' :
$ awk 'NR==1{printf "%s %s\n", $0, "ok"}' /etc/passwd
root:x:0:0:root:/root:/bin/bash ok
To edit a file, you can use ed, the standard editor:
line=' bcm2708.w1_gpio_pin=20'
file=/boot/cmdline.txt
if ! grep -q -x -F -e "$line" <"$file"; then
ed -s "$file" < <(printf '%s\n' 1 a "$line" . 1,2j w q)
fi
ed's commands:
1: go to line 1
a: append (this will insert after the current line)
We're in insert mode and we're inserting the expansion of $line
.: stop insert mode
1,2j join lines 1 and 2
w: write
q: quit
This can be used to append a variable to the first line of input:
awk -v suffix="$suffix" '{print NR==1 ? $0 suffix : $0}'
This will work even if the variable could potentially contain regex formatting characters.
Example:
suffix=' [first line]'
cat input.txt | awk -v suffix="$suffix" '{print NR==1 ? $0 suffix : $0}' > output.txt
input.txt:
Line 1
Line 2
Line 3
output.txt:
Line 1 [first line]
Line 2
Line 3
This question already has answers here:
How can I replace each newline (\n) with a space using sed?
(43 answers)
Closed 8 years ago.
I have an XML file which has occasional lines that are split into 2: the first line ending with
. I want to concatenate any such lines and remove the
, perhaps replacing it with a space.
e.g.
<message>hi I am
here </message>
needs to become
<message>hi I am here </message>
I've tried:
sed -i 's/
\/n/ /g' filename
with no luck.
Any help is much appreciated!
Here is a GNU sed version:
sed ':a;$bc;N;ba;:c;s/
\n/ /g' file
Explanation:
sed '
:a # Create a label a
$bc # If end of file then branch to label c
N # Append the next line to pattern space
ba # branch back to label a to repeat until end of file
:c # Another label c
s/
\n/ /g # When end of file is reached perform this substitution
' file
give this gawk one-liner a try:
awk -v RS="" 'gsub(/
\n/," ")+7' file
tested here with your example:
kent$ echo "<message>hi I am
here </message>"|awk -v RS="" 'gsub(/
\n/," ")+7'
<message>hi I am here </message>
You can use this awk:
awk -F"
" '/
$/ {a=$1; next} a{print a, $0; a=""; next} 1' file
Explanation
-F"
" set
as delimiter, so that the first field will be always the desired part of the string.
/
$/ {a=$1; next} if the line ends with
, store it in a and jump to the next line.
a{print a, $0; a=""; next} if a is set, print it together with current line. Then unset a for future loops. Finally jump to next line.
1 as true, prints current line.
Sample
$ cat a
yeah
<message>hi I am
here </message>
hello
bye
$ awk -F"
" '/
$/ {a=$1; next} a{print a, $0; a=""; next} 1' a
yeah
<message>hi I am here </message>
hello
bye
This will work for you:
sed -i '{:q;N;s/&.*\n/ /g;t q}' <filename>
However replacing newline with sed is always a bash(read bad) idea. Chances of making an error are high.
So another but simpler solution:
tr -s '\&\#13\;\n' ' ' < <filename>
tr is replacing all chracter in match with space, so without -s it would have printed
<message>hi I am here </message>
-s from man page:
-s, --squeeze-repeats
replace each input sequence of a repeated character that is listed in SET1 with a single occurrence of that character.
I have a text file which contains some lines as the following:
ASDASD2W 3ASGDD12 SDADFDFDDFDD W11 ACC=PNO23 DFSAEFEA EAEDEWRESAD ASSDRE
AERREEW2 3122312 SDADDSADADAD W12 ACC=HH34 23SAEFEA EAEDEWRESAD ASEEWEE
A15ECCCW 3XCXXF12 SDSGTRERRECC W43 ACC=P11 XXFSAEFEA EAEDEWRESAD ASWWWW
ASDASD2W 3122312 SDAFFFDEEEEE SD3 ACC=PNI22 ABCEFEA EAEDEWRESAD ASWEDSSAD
...
I have to extract the substring between the '=' character and the following blank space for each line , i.e.
PNO23
HH34
P11
PNI22
I've been using the sed command but cannot figure out how to ignore all characters following the blank space.
Any help?
Use the right tool for the job.
$ awk -F '[= ]+' '{ print $6 }' input.txt
PNO23
HH34
P11
PNI22
Sorry, but have to add another one because I feel the existing answers are just to complicated
sed 's/.*=//; s/ .*//;' inputfile
This might work for you:
sed -n 's/.*=\([^ ]*\).*/\1/p' file
or, if you prefer:
sed 's/.*=\([^ ]*\).*/\1/p;d' file
Put the string you want to capture in a backreference:
sed 's/.*=\([^ =]*\) .*/\1/'
or do the substitution piecemeal;
sed -e 's/.*=//' -e 's/ .*//'
sed 's/[^=]*=\([^ ]*\) .*/\1/' inputfile
Match all the non-equal-sign characters and an equal sign. Capture a sequence of non-space characters. Match a space and the rest of the line. Substitute the captured string.
A chain of grep can do the trick.
grep -o '[=][a-zA-Z0-9]*' file | grep -o '[a-zA-Z0-9]*'