I am trying to use sed in a script but it keeps failing. The commands on their own seem to work so I am not sure what I am doing wrong:
This is in Terminal in OS X (bash)
NOTE: file1.txt contains multiple lines of text
N=1
sed -n $Np < file1.txt > file2.txt
CONTENT=$(cat file2.txt)
echo $CONTENT
If I change $N to 1, it works perfectly
sed -n 1p <file1.txt >file2.txt
CONTENT=$(cat file2.txt)
echo $CONTENT
gives me
content of file2.txt
So basically, I am trying to copy the text from line 1 of a file to the start of line 2 of a file ... IF line 2 does not already start with the content of line 1.
The shell doesn't know that you want $N and not $Np.
Do this: ${N}p
Change:
sed -n $Np < file1.txt > file2.txt
to
sed -n ${N}p < file1.txt > file2.txt
You code has no clue what variable Np is...
Since N was an integer, I ended up using the following.
sed -n `expr $N`p < file1 > file2
This also allows me to get the next line in a file using
sed -n `expr $N+1`p < file1 > file2
Thanks for your help!!!
You should use >> for append redirection. > overwrites the original file.
How to append the output to a file?
Related
I have a line like this:
INPUT file1
How can I get bash to read that line and directly copy in the contents of "file1.txt" in place of that line? Or if it sees: INPUT file2 on a line, put in `file2.txt" etc.
The best I can do is a lot of tr commands, to paste the file together, but that seems an overly complicated solution.
'sed' also replaces lines with strings, but I don't know how to input the entire content of a file, which can be hundreds of lines into the replacement.
Seems pretty straightforward with awk. You may want to handle errors differently/more gracefully, but:
$ cat file1
Line 1 of file 1
$ cat file2
Line 1 of file 2
$ cat input
This is some content
INPUT file1
This is more content
INPUT file2
This file does not exist
INPUT file3
$ awk '$1=="INPUT" {system("cat " $2); next}1' input
This is some content
Line 1 of file 1
This is more content
Line 1 of file 2
This file does not exist
cat: file3: No such file or directory
A perl one-liner, using the CPAN module Path::Tiny
perl -MPath::Tiny -pe 's/INPUT (\w+)/path("$1.txt")->slurp/e' input_file
use perl -i -M... to edit the file in-place.
Not the most efficient possible way, but as an exercise I made a file to edit named x and a couple of input sources named t1 & t2.
$: cat x
a
INPUT t2
b
INPUT t1
c
$: while read k f;do sed -ni "/$k $f/!p; /$k $f/r $f" x;done< <( grep INPUT x )
$: cat x
a
here's
==> t2
b
this
is
file ==> t1
c
Yes, the blank lines were in the INPUT files.
This will sed your base file repeatedly, though.
The awk solution given is better, as it only reads through it once.
If you want to do this in pure Bash, here's an example:
#!/usr/bin/env bash
if (( $# < 1 )); then
echo "Usage: ${0##*/} FILE..."
exit 2
fi
for file; do
readarray -t lines < "${file}"
for line in "${lines[#]}"; do
if [[ "${line}" == "INPUT "* ]]; then
cat "${line#"INPUT "}"
continue
fi
echo "${line}"
done > "${file}"
done
Save to file and run like this: ./script.sh input.txt (where input.txt is a file containing text mixed with INPUT <file> statements).
Sed solution similar to awk given erlier:
$ cat f
test1
INPUT f1
test2
INPUT f2
test3
$ cat f1
new string 1
$ cat f2
new string 2
$ sed 's/INPUT \(.*\)/cat \1/e' f
test1
new string 1
test2
new string 2
test3
Bash variant
while read -r line; do
[[ $line =~ INPUT.* ]] && { tmp=($BASH_REMATCH); cat ${tmp[1]}; } || echo $line
done < f
I have an input file containing the following numbers
-45.0005
-43.0022
-41.002
.
.
.
I have a target txt file
line:12 Angle=30
line:42 Angle=60
line:72 Angle=90
.
.
.
Using sed I want to replace the first instance of Angle entry in the target file with the first entry from the input file, the second entry of Angle with the second entry of the input file so and so forth...
Expected output:
line:12 Angle=-45.005
line:42 Angle=-43.002
line:72 Angle=-41.002
.
.
.
This is what I have managed to write but I am not getting the expected output
a=`head -1 temp.txt`
#echo $a
sed -i "12s/Angle = .*/Angle = $a/g" $procfile
for i in {2..41..1}; do
for j in {42..1212..30}; do
c=$(( $i - 1 ))
#echo "this is the value of c: $c"
b=`head -$i temp.txt | tail -$c`
#echo "This is the value of b: $b"
sed -i "$js/Angle = .*/Angle = $b/g" $procfile 2> /dev/null
done
done
Could you help me improve the script?
Thanks!
You may create an iterator i and then use it in sed to perform substitution in each line.
i=0;
while read -r line; do
i=$((i+1));
sed -i "${i}s/Angle=.*/Angle=${line}/g" $procfile;
done < temp.txt
So I guess you want to paste files - marge files line by line. Then replace the field with a regex for example.
paste target_file input_file | sed 's/\(Angle=\)[^\t]*\t/\1/'
This might work for you (GNU sed):
sed '/Angle=/R inputFile' targetFile | sed '/Angle=/{N;s/=.*\n/=/}'
In the first sed invocation append the input line.
In the second sed invocation remove the original angle and the newline delimiter.
pr might help here, please try this:
pr -m -t target input | sed -r 's/(Angle=)[^\s]+\s+/\1/'
Please note - this works for your first two showed files, your code assumes some different input - e.g. spaces around "=".
So I was able to come up with this solution
#!/bin/bash
infile=$1
cp $infile ORIG_${infile}
grep "Angle = " $infile | sed 's/Angle = //g' | sort -n > temp.txt
iMax=`cat temp.txt | wc -l`
jMax=`grep -n "Angle = " $infile | tail -1 | sed 's/:.*//g'`
for ((i=1,j=12; i<=${iMax} && j<=${jMax};i+=1,j+=30));do
a=`head -$i temp.txt | tail -1`
sed -i "${j}s/Angle = .*/Angle = $a/g" $infile
done
rm temp.txt
Many thanks to william pursell for clarifying the syntax for incrementing var counts in bash.
I would like to remove a file name only from the following configuration file.
Configuration File -- test.conf
knowledgebase/arun/test.rf
knowledgebase/arunraj/tester/test.drl
knowledgebase/arunraj2/arun/test/tester.drl
The above file should be read. And removed contents should went to another file called output.txt
Following are my try. It is not working to me at all. I am getting empty files only.
#!/bin/bash
file=test.conf
while IFS= read -r line
do
# grep --exclude=*.drl line
# awk 'BEGIN {getline line ; gsub("*.drl","", line) ; print line}'
# awk '{ gsub("/",".drl",$NF); print line }' arun.conf
# awk 'NF{NF--};1' line arun.conf
echo $line | rev | cut -d'/' -f 1 | rev >> output.txt
done < "$file"
Expected Output :
knowledgebase/arun
knowledgebase/arunraj/tester
knowledgebase/arunraj2/arun/test
There's the dirname command to make it easy and reliable:
#!/bin/bash
file=test.conf
while IFS= read -r line
do
dirname "$line"
done < "$file" > output.txt
There are Bash shell parameter expansions that will work OK with the list of names given but won't work reliably for some names:
file=test.conf
while IFS= read -r line
do
echo "${line%/*}"
done < "$file" > output.txt
There's sed to do the job — easily with the given set of names:
sed 's%/[^/]*$%%' test.conf > output.txt
It's harder if you have to deal with names like /plain.file (or plain.file — the same sorts of edge cases that trip up the shell expansion).
You could add Perl, Python, Awk variants to the list of ways of doing the job.
You can get the path like this:
path=${fullpath%/*}
It cuts away the string after the last /
Using awk one liner you can do this:
awk 'BEGIN{FS=OFS="/"} {NF--} 1' test.conf
Output:
knowledgebase/arun
knowledgebase/arunraj/tester
knowledgebase/arunraj2/arun/test
I have number of files which have similar names like
DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out
DWH_Export_AUSTA_20120701_20120731_v1_2.csv.397.dat.2012-10-02 04-03-12.out
DWH_Export_AUSTA_20120801_20120831_v1_1.csv.397.dat.2012-10-02 04-04-16.out
etc.
I need to get number before .csv(1 or 2) from the file name and put it into end of every line in file with TAB separator.
I have written this code, it finds number that I need, but i do not know how to put this number into file. There is space in the filename, my script breaks because of it.
Also I am not sure, how to send to script list of files. Now I am working only with one file.
My code:
#!/bin/sh
string="DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out"
out=$(echo $string | awk 'BEGIN {FS="_"};{print substr ($7,0,1)}')
awk ' { print $0"\t$out" } ' $string
for file in *
do
sfx=$(echo "$file" | sed 's/.*_\(.*\).csv.*/\1/')
sed -i "s/$/\t$sfx/" "$file"
done
Using sed:
$ sed 's/.*_\(.*\).csv.*/&\t\1/' file
DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out 1
DWH_Export_AUSTA_20120701_20120731_v1_2.csv.397.dat.2012-10-02 04-03-12.out 2
DWH_Export_AUSTA_20120801_20120831_v1_1.csv.397.dat.2012-10-02 04-04-16.out 1
To make this for many files:
sed 's/.*_\(.*\).csv.*/&\t\1/' file1 file2 file3
OR
sed 's/.*_\(.*\).csv.*/&\t\1/' file*
To make this changed get saved in the same file(If you have GNU sed):
sed -i 's/.*\(.\).csv.*/&\t\1/' file
Untested, but this should do what you want (extract the number before .csv and append that number to the end of every line in the .out file)
awk 'FNR==1 { split(FILENAME, field, /[_.]/) }
{ print $0"\t"field[7] > FILENAME"_aaaa" }' *.out
for file in *_aaaa; do mv "$file" "${file/_aaaa}"; done
If I understood correctly, you want to append the number from the filename to every line in that file - this should do it:
#!/bin/bash
while [[ 0 < $# ]]; do
num=$(echo "$1" | sed -r 's/.*_([0-9]+).csv.*/\t\1/' )
#awk -e "{ print \$0\"\t${num}\"; }" < "$1" > "$1.new"
#sed -r "s/$/\t$num/" < "$1" > "$1.mew"
#sed -ri "s/$/\t$num/" "$1"
shift
done
Run the script and give it names of the files you want to process. $# is the number of command line arguments for the script which is decremented at the end of the loop by shift, which drops the first argument, and shifts the other ones. Extract the number from the filename and pick one of the three commented lines to do the appending: awk gives you more flexibility, first sed creates new files, second sed processes them in-place (in case you are running GNU sed, that is).
Instead of awk, you may want to go with sed or coreutils.
Grab number from filename, with grep for variety:
num=$(<<<filename grep -Eo '[^_]+\.csv' | cut -d. -f1)
<<<filename is equivalent to echo filename.
With sed
Append num to each line with GNU sed:
sed "s/\$/\t$num" filename
Use the -i switch to modify filename in-place.
With paste
You also need to know the length of the file for this method:
len=$(<filename wc -l)
Combine filename and num with paste:
paste filename <(seq $len | while read; do echo $num; done)
Complete example
for filename in DWH_Export*; do
num=$(echo $filename | grep -Eo '[^_]+\.csv' | cut -d. -f1)
sed -i "s/\$/\t$num" $filename
done
i am trying to read a text file, say file.txt and it contains multiple lines.
say the output of file.txt is
$ cat file.txt
this is line 1
this is line 2
this is line 3
I want to store the entire output as a variable say, $text.
When the variable $text is echoed, the expected output is:
this is line 1 this is line 2 this is line 3
my code is as follows
while read line
do
test="${LINE}"
done < file.txt
echo $test
the output i get is always only the last line. Is there a way to concatenate the multiple lines in file.txt as one long string?
You can translate the \n(newline) to (space):
$ text=$(tr '\n' ' ' <file.txt)
$ echo $text
this is line 1 this is line 2 this is line 3
If lines ends with \r\n, you can do this:
$ text=$(tr -d '\r' <file.txt | tr '\n' ' ')
Another one:
line=$(< file.txt)
line=${line//$'\n'/ }
test=$(cat file.txt | xargs)
echo $test
You have to append the content of the next line to your variable:
while read line
do
test="${test} ${LINE}"
done < file.txt
echo $test
Resp. even simpler you could simply read the full file at once into the variable:
test=$(cat file.txt)
resp.
test=$(tr "\n" " " < file.txt)
If you would want to keep the newlines it would be as simple as:
test=<file.txt
I believe it's the simplest method:
text=$(echo $(cat FILE))
But it doesn't preserve multiple spaces/tabs between words.
Use arrays
#!/bin/bash
while read line
do
a=( "${a[#]}" "$line" )
done < file.txt
echo -n "${a[#]}"
output:
this is line 1 this is line 2 this is line 3
See e.g. tldp section on arrays