I am just learning to work with csv files from the command line. I want to delete several lines from a file using sed. I've removed the header of a file with this cat file.csv | sed 1,2d > file.csv.
Now I want to delete several more lines from the file (lines 3, 10, 12, and 28-35) and I am not sure how to pull it off. I'd be grateful for any help.
Depending on the sed implementation, you could separate them as follows:
cat file.csv | sed "1,2d;10d;12d;28,35d" > file2.csv
Use the -e flag to pass several commands to one sed invocation, like this:
seq 1 40 | sed -e 1,2d -e 3d -e 10d -e 12d -e 28,35d
Related
Hello everyone I am trying to delete lines using sed command:
What I have right now is :
$comp_args = "$comp_args -cover bsceft"
Output: I want to get rid off this line .
I tried this :
cat <path to file > |\ sed '/comp_args -cover bsceft/d' |\ > <path_to_file>
Seems to be not working.
I'd use ed instead of sed if you want to make changes the file in-place, as it, unlike sed, was designed from the start to edit files.
printf "%s\n" "/comp_args -cover bscheft/d" w | ed -s yourfile
will delete the first matching line and save the modified file.
I'm debugging a shell script and trying to find out the task performed by the following command:
sed -i '1,+999d' /home/org_user/data.txt
I need to change this command as its failing with the following error:
illegal option sed -i
But before changing, I need to understand the BAU functioning.
Appreciate any inputs in this regard.
An applicable use of this is as follows. Say you have the following file file.txt:
1, 2, 6, 7, "p"
We want to replace "p" with 0.
sed 's/"p"/0/g' file.txt
Using the above simply prints the output into command line.
You'd think why not just redirect that text back into the file like this:
sed 's/"p"/0/g' file.txt > file.txt
Unfortunately because of the nature of redirects the above will simply produce a blank file.
Instead a temp file must be created for the output which later overwrites the original file something like this:
sed 's/"p"/0/g' file.txt > tmp.txt && mv tmp.txt file.txt
Instead of doing the long workaround above sed edit in place option with -i allows for a much simpler command:
sed -i 's/"p"/0/g' file.txt
If -i option given, sed edit files in place.
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if extension supplied)
from sed(1)
http://www.gnu.org/software/sed/manual/sed.html#Introduction
Some implementations of sed do not support the -i option. What it does can be simulated by
sed -e '...' file > tmp
mv tmp file
I am having a log file a.log and i need to extract a piece of information from it.
To locate the start and end line numbers of the pattern i am using the following.
start=$(sed -n '/1112/=' file9 | head -1)
end=$(sed -n '/true/=' file9 | head -1)
i need to use the variables (start,end) in the following command:
sed -n '16q;12,15p' orig-data-file > new-file
so that the above command appears something like:
sed -n '($end+1)q;$start,$end'p orig-data-file > new-file
I am unable to replace the line numbers with the variables. Please suggest the correct syntax.
Thanks,
Rosy
When I realized how to do it, I was looking for anyway to get line number into a file containing the requested info, and display the file from that line to EOF.
So, this was my way.
with
PATTERN="pattern"
INPUT_FILE="file1"
OUTPUT_FILE="file2"
line number of first match of $PATTERN into $INPUT_FILE can be retrieved with
LINE=`grep -n ${PATTERN} ${INPUT_FILE} | awk -F':' '{ print $1 }' | head -n 1`
and the outfile will be the text from that $LINE to EOF. This way:
sed -n ${LINE},\$p ${INPUT_FILE} > ${OUTPUT_FILE}
The point here, is the way how can variables be used with command sed -n:
first witout using variables
sed -n 'N,$p' <file name>
using variables
LINE=<N>; sed -n ${LINE},\$p <file name>
Remove the single quotes thus. Single quotes turn off the shell parsing of the string. You need shell parsing to do the variable string replacements.
sed -n '('$end'+1)q;'$start','$end''p orig-data-file > new-file
Recently I came across following grep command:
/usr/xpg4/bin/grep -Ff grep.txt input.txt > output.txt
which as per my understanding means that from input.txt, grep the matter contained in grep.txt and output it to output.txt.
I want to do something similar for sed i.e. I want to keep the sed commands in a separate file (say sed.txt) and want to apply them on input file (say input.txt) and create a output file (say output.txt).
I tried following:
/usr/xpg4/bin/sed -f sed.txt input.txt > output.txt
It does not work and I get the following error:
sed: command garbled
The contents of files mentioned above are as below:
sed.txt
sed s/234/acn/ input.txt
sed s/78gt/hit/ input.txt
input.txt
234GH
5234BTW
89er
678tfg
234
234YT
tfg456
wert
78gt
gh23444
Your sed.txt should only contain sed commands: No prefixing with sed or suffixing with an input file. In your case it should probably be:
# sed.txt
s/234/acn/
s/78gt/hit/
When ran on your input:
$ /usr/xpg4/bin/sed -f sed.txt input.txt
acnGH
5acnBTW
89er
678tfg
acn
acnYT
tfg456
wert
hit
ghacn44
Rather than keeping the sed commands in a separate text file, you may want to try creating a sed script. The file below can run directly on your data files:
./myscript.sed inputfile.txt > outputfile.txt
#!/bin/sed -f
s/234/acn/
s/78gt/hit/
I tried to insert a text to the first line
of a file using sed. I do this inside a sh
script.
But why it hangs at the line of sed execution?
#! /bin/sh
# Command to execute
# ./mybashcode.sh test.nbq
nbqfile=$1
nbqbase=$(basename $nbqfile nbq)
taglistfiletemp="${nbqbase}taglist_temp"
taglistfile="${nbqbase}taglist"
./myccode $nbqfile |
sort |
uniq -c |
awk '{print $2}' > $taglistfiletemp
noftags=$(wc -l $taglistfiletemp | awk '{print $1}')
echo $noftags
# We want to append output of noftags
# to the first line of taglistfile
sed '1i\
$noftags' > $taglistfile
# why it hangs here
# the content of taglistfile is NIL
I'm not sure what you are trying to do with sed but it needs two inputs, the script (usually a search/replace) and the data you want to perform it on. If you only specify one it assumes it has got the regular expression and waits for data on stdin. As you haven't supplied anything on stdin it'll hang indefinitely.
In addition, you have '$noftags' rather than "$noftags". The prior will output $noftags and the latter the contents of the variable, as single quotes do not allow variable expansion.
Have I got something wrong here?
Or, all you want to do is insert some text at the start of another file?
# $NewInitialText
# $fileToInsertInto
echo $NewInitialText > temp.file.txt
cat $fileToInsertInto >> temp.file.txt
mv temp.file.txt $fileToInsertInto
Is that easier done than sed? -- Pun intended I guess.
it hangs because you forget to supply sed with the input file.
....
...
sed -i.bak "1i $noftags" $taglistfile
...