I'd like to read connectedclients.now line by line, doing something while read each, and delete the line when done the work.
Actually tried:
ClientWork.sh:
unset n
while read -r user work codename; do
echo $user $work $codename
: $[n++]
done <connectedclients.now
sed "1 $n d" connectedclients.now
Original code from stackexchange
Getting sed: -e expression #1, char 5: unexpected,'` as an issue. Any ideas to fix it?
Your arithmetic is wrong: $[n++], instead try :
((n++))
Check http://mywiki.wooledge.org/ArithmeticExpression
and if you want to remove line by line :
n=0
while read -r user work codename; do
echo "$user $work $codename"
((n++))
sed -i "$n d" connectedclients.now
done < connectedclients.now
If you really really need to remove lines as you're processing each line, I'd first read the whole file:
file=connectedclients.now
echo "before processing, $(wc -l < "$file") lines"
mapfile -t all_lines < "$file"
for line in "${all_lines[#]}"; do
read -r user work codename <<<"$line"
echo $user $work $codename
sed -i 1d "$file"
done
echo "after processing, $(wc -l < "$file") lines"
Related
I am reading a file with lines like:
folder=abc
name=xyz
For some lines line I would like set a variable e.g name=xyz corresponding to the line I have read.
Cutting it down, with name=xyz and folder=abc, I have tried:
while read -r line; do
$line
echo $name
done < /etc/testfile.conf
This gives an error message ./test: line 4: folder=abc: command not found etc.
I have tried "$line" and $($line) and it is the same. Is it possible to do what I whant?
I have succeeded by doing:
while read -r line; do
if [[ "$line" == 'folder'* ]]; then
folder="$(echo "$line" | cut -d'=' -f 2)"
fi
if [[ "$line" == 'name'* ]]; then
name="$(echo "$line" | cut -d'=' -f 2)"
fi
done < /etc/testfile.conf
but this seems messy
for your sample, declare is the safest option:
while read -r line; do
declare "$line"
done
$ echo "$folder"
abc
$ echo "$name"
xyz
Direct approach, use eval.
Different approach, try with source or .:
$ echo "$line"
folder=abc
$ . <(echo "$line")
$ echo "$folder"
abc
But probably the good answer will be to tackle the problem in a different way.
You can clean up your approach a bit without resorting to eval.
while IFS="=" read -r name value; do
case $name in
folder) folder=$value ;;
name) name=$value ;;
esac
done < /etc/testfile.conf
why not only source de file ?
$ . infile ; echo "$name"
xyz
I don't understand why this outer loop exits just because the inner loop can finish.
The $1 refers to a file with a lot of pattern/replacement lines. The $2 is a list of words. The problem is that the outer loop exits already after the first pattern/replacement line. I want it to exit after all the lines in $1 are read.
#!/bin/bash
#Receive SED SCRIPT WORDLIST
if [ -f temp.txt ];
then
> temp.txt
else
touch temp.txt
fi
while IFS='' read -r line || [[ -n "$line" ]];
do
echo -e "s/$line/p" >> temp.txt
while IFS='' read -r line || [[ -n "$line" ]];
do
sed -nf temp.txt $2
done
> temp.txt
done < $1
I understand that you want calculate de sed expressions and write it on a file, and then apply this expresions to other file.
This is so much easier than your are doing it.
First of all, you dont need to check if temp.txt already exists. When you redirect the output of a command to a file, if this file do not exist, it will be created. But if you want to reset the file, I recommend you to use truncate command.
In the body of the script, I don't understand why you put a second while loop to read from a file, but you don't put a file to read.
I think that you need is something like this:
truncate -s 0 sed_expressions.txt
while IFS='' read -r line || [[ -n "$line" ]]; do
echo -e "s/$line/p" >> sed_expressions.txt
done < $1
sed -nf sed_expressions.txt $2 > out_file.txt
Try it and tell me if is this that you need.
Bye!
I need you help on this;
I am currently trying to apply a sed command to lines from a file.
2014-08-05T09:29:13+01:00 (INFO:3824.87075728): [27219] [ <email#domain.com>] A message from <user1#domain.com> source <asdfg> this is a test.
I need to apply this sed cmd to this line but keep this others that does not have 'this is a test'
pattern="this\ is\ a test"
while IFS='' read -r line; do
if [[ $line = *"${pattern}"* ]]; then
sed 's/\[ .*\(source\)/\1/g' ${line}
else
echo "${line}"
fi
done < ${INPUT} > ${OUPUT}
I have set the input and output; however ideally keeping the same file would be ideal.
Thank you for your input.
You don't need a loop for this. Use this sed:
sed -i.bak '/this is a test/s/\[ .*\(source\)/\1/g' "${INPUT}"
I want convert a column of data in a txt file to a row of a csv file using unix commands.
example:
ApplChk1,
ApplChk2,
v_baseLoanAmountTI,
v_plannedClosingDateField,
downPaymentTI,
this is a column which present in a txt file
I want output as follows in a csv file
ApplChk1,ApplChk2,v_baseLoanAmountTI,v_plannedClosingDateField,downPaymentTI,
Please let me know how to do it.
Thanks in advance
If that's a single column, which you want to convert to row, then there are many possibilities:
tr -d '\n' < filename ; echo # option 1 OR
xargs echo -n < filename ; echo # option 2 (This option however, will shrink spaces & eat quotes) OR
while read x; do echo -n "$x" ; done < filename; echo # option 3
Please let us know, how the input would look like, for multi-line case.
A funny pure bash solution (bash ≥ 4.1):
mapfile -t < file.txt; printf '%s' "${MAPFILE[#]}" $'\n'
Done!
for i in `< file.txt` ; do echo -n $i; done; echo ""
gives the output
ApplChk1,ApplChk2,v_baseLoanAmountTI,v_plannedClosingDateField,downPaymentTI,
To send output to a file:
{ for i in `< file.txt` ; do echo -n $i ; done; echo; } > out.csv
When I run it, this is what happens:
[jenny#jennys:tmp]$ more file.txt
ApplChk1,
ApplChk2,
v_baseLoanAmountTI,
v_plannedClosingDateField,
downPaymentTI,
[jenny#jenny:tmp]$ { for i in `< file.txt` ; do echo -n $i ; done; echo; } > out.csv
[jenny#jenny:tmp]$ more out.csv
ApplChk1,ApplChk2,v_baseLoanAmountTI,v_plannedClosingDateField,downPaymentTI,
perl -pe 's/\n//g' your_file
the above will output to stdout.
if you want to do it in place:
perl -pi -e 's/\n//g' your_file
You could use the Linux command sed to replace line \n breaks by commas , or space :
sed -z 's/\n/,/g' test.txt > test.csv
You could also add the -i option if you want to change file in-place :
sed -i -z 's/\n/,/g' test.txt
I am trying to write a script which reads a text file and saves each line to a string. I would also like the script to skip any lines which start with a hash symbol. Any suggestions?
You should not leave skipping lines to ksh. E.g. do this:
grep -v '^#' INPUTFILE | while IFS="" read line ; do echo $line ; done
And instead of the echo part do whatever you want.
Or if ksh does not support this syntax:
grep -v '^#' INPUTFILE > tmpfile
while IFS="" read line ; do echo $line ; done < tmpfile
rm tmpfile
while read -r line; do
[[ "$line" = *( )#* ]] && continue
# do something with "$line"
done < filename
look for "File Name Patterns" or "File Name Generation" in the ksh man page.