I would like to grep for "String = " and when nothing is mentioned...when it's empty...echo with an if then else statement:
I tried something like that:
if grep "String" input.txt | sed -e 's/ String = //g' | egrep -q "^$"
then
<command> > output.txt
else
echo "--" > output.txt
fi
When I use the sed command the line is empty.
Thx in advance!
UPDATE
these are some possible lines in input.txt
String = TextA
String =
String = TextB
You can just use this grep to check for String = in the input file:
if grep -Eq 'String *= *$' input.txt; then
<command> > output.txt
else
echo "--" > output.txt
fi
You might consider using awk:
CMD=$(awk '$1=="String" {print $3}' input.txt)
if [ -n "$CMD" ]
then
CMD="--"
fi
echo "$CMD" > output.txt
some explanations:
awk prints the third column (since there is a space before and after the = sign; that is the 2nd column)
the line if [ -n "$CMD" ] just tests if the variable CMD is empty
From your question, I assume you are having trouble finding the specified lines in the file. The following grep command will find those lines:
egrep 'String[[:space:]]*=[[:space:]]*' input.txt
Adapt it to your if/else statements and it should work.
Or, if you want to specify that there is one space before the "=", do:
egrep 'String[[:space:]]{1}=[[:space:]]*;
Related
When I try to extract rows that are matched string which are in another file.But the grep command returns nothing.
#!/bin/bash
input="export.txt"
file="filename.csv"
val=`head -n 1 $file`
echo $val>export.csv
cat export.txt | while read line
do
val=`echo $line | tr -d '\n'`
echo $val
valu=`grep $val $file`
echo $valu
done
You can simply do this :
grep -f list.txt input.txt
Which will extract all the lines from input which match any word from list.txt.
If for some reason you want to save each match, you can do it in a Bash array as :
IFS=$'\n' read -d '' -a values <<< "$( grep -f list.txt input.txt )"
And then you can print a certain match as :
echo "${values[1]}"
Regards!
Is it possible in bash to filter out a part of a string with another given string ?
I have a fixed list of motifs defined in a string. The order IS important and I want to keep only the parts that are passed as a parameter ?
myDefaultList="s,t,a,c,k" #order is important
toRetains="k,t,c,u" #provided by the user, order is not enforced
retained=filter $myDefaultList $toRetains # code to filter
echo $retained # will print t,c,k"
I can write an ugly method that will use IFS, arrays and loops, but I wonder if there's a 'clever' way to do that, using built-in commands ?
here is another approach
tolines() { echo $1 | tr ',' '\n'; }
grep -f <(tolines "$toRetains") <(tolines "$myDefaultList") | paste -sd,
will print
t,c,k
assign to a variable as usual.
Since you mention in your comments that you are open to sed/awk , check also this with GNU awk:
$ echo "$a"
s,t,a,c,k
$ echo "$b"
k,t,c,u
$ awk -v RS=",|\n" 'NR==FNR{a[$1];next}$1 in a{printf("%s%s",$1,RT)}' <(echo "$b") <(echo "$a")
t,c,k
#!/bin/bash
myDefaultList="s,t,a,c,k"
toRetains="s,t,c,u"
IFS=","
for i in $myDefaultList
do
echo $toRetains | grep $i > /dev/null
if [ "$?" -eq "0" ]
then
retained=$retained" "$i
fi
done
echo $retained | sed -e 's/ /,/g' -e 's/,//1'
I have checked it running for me. Kindly check.
file=$2
isHeader=$true
while read -r line;
do
if [ $isHeader ]
then
sed "1i$line",\"BATCH_ID\"\n >> $file
else
sed "$line,1"\a >> $file
fi
isHeader=$false
done < $1
echo $file
In the first line I want to append a string and to the others lines I want to append the same string for the rest of the lines. I tried this but it doesn't work. I don't have any ideas, can somebody help me please?
Not entirely clear to me what you want to do, but if you simply want to append text at the end of each line, use echo in place of sed:
file=$2
isHeader=1
while read -r line;
do
if [ $isHeader ]
then
#sed "1i$line",\"BATCH_ID\"\n >> $file
echo "${line},\"BATCH_ID\"\n" > $file
else
#sed "$line,1"\a >> $file
echo "${line},1\a" >> $file
fi
isHeader=0
done < $1
cat $file
The accepted answer is slightly wrong because echo...\a produces a bell. Also, awk or sed support regular expressions and are 10x faster at line-by-line processing. Here it is in awk:
#! /bin/sh
script='NR == 1 { print $0 ",\"BATCH_ID\"" }
NR > 1 { print $0 ",1" }'
awk "$script" $1 > $2
In sed it's even simpler:
sed '1 s/$/,"BATCH_ID"/; 2,$ s/$/,1/' $1 > $2
To convince yourself of the speed, try this yourself:
$ time seq 100000 | while read f; do echo ${f}foo; done > /dev/null
real 0m2.068s
user 0m1.708s
sys 0m0.364s
$ time seq 100000 | sed 's/$/foo/' > /dev/null
real 0m0.166s
user 0m0.156s
sys 0m0.017s
I'm processing some data from a text file using a bash script (Ubuntu 12.10).
The basic idea is that I select a certain line from a file using grep. Next, I process the line to get the number with sed. Both the grep and sed command are working. I can echo the number.
But the concatenation of the result with a string goes wrong.
I get different results when combining string when I do a grep command from a variable or a file. The concatenation goes wrong when I grep a file. It works as expected when I grep a variable with the same text as in the file.
What am I doing wrong with the grep from a file?
Contents of test.pdb
REMARK overall = 324.88
REMARK bon = 24.1918
REMARK coup = 0
My script
#!/bin/bash
#Correct function
echo "Working code"
TEXT="REMARK overall = 324.88\nREMARK bon = 24.1918\nREMARK coup = 0\n"
DATA=$(echo -e $TEXT | grep 'overall' | sed -n -e "s/^.*= //p" )
echo "Data: $DATA"
DATA="$DATA;0"
echo $DATA
#Not working
echo ""
echo "Not working code"
DATA=$(grep 'overall' test.pdb | sed -n -e "s/^.*= //p")
echo "Data: $DATA"
DATA="$DATA;0"
echo $DATA
Output
Working code
Data: 324.88
324.88;0
Not working code
Data: 324.88
;04.88
I went crazy with the same issue.
The real problem is that your "test.pdb" has probably a wrong EOL (end of line) character.
Linux EOL: LF (aka \n)
Windows EOL: CR LF (aka \r \n)
This mean that echo and grep will have problem with this extra character (\r), luckily tr, sed and awk manage it correctly.
So you can try also with:
DATA=$(grep 'overall' test.pdb | sed -n -e "s/^.*= //p" | sed -e 2s/\r$//")
or
DATA=$(grep 'overall' test.pdb | sed -n -e "s/^.*= //p" | tr -d '\r')
With awk, it will be more reliable and cleaner I guess :
$ awk '$2=="overall"{print "Working code\nData: " $4 "\n" $4 ";0"}' file.txt
Working code
Data: 324.88
324.88;0
Try this:
SUFFIX=";0"
DATA="${DATA}${SUFFIX}"
I want convert a column of data in a txt file to a row of a csv file using unix commands.
example:
ApplChk1,
ApplChk2,
v_baseLoanAmountTI,
v_plannedClosingDateField,
downPaymentTI,
this is a column which present in a txt file
I want output as follows in a csv file
ApplChk1,ApplChk2,v_baseLoanAmountTI,v_plannedClosingDateField,downPaymentTI,
Please let me know how to do it.
Thanks in advance
If that's a single column, which you want to convert to row, then there are many possibilities:
tr -d '\n' < filename ; echo # option 1 OR
xargs echo -n < filename ; echo # option 2 (This option however, will shrink spaces & eat quotes) OR
while read x; do echo -n "$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