I have a file text titled test.txt containing
1 2 3 4
2 3 4
1 12 2 4 5 66
I would like to read it line by line and for each line I would like to extract the elements.
I tried with
while read lines;
do
echo $lines
done < test.txt
It prints correctly the lines of the matrix saved in the txt file but now I don't know how extract the single elements from the variable lines...
I would like to do something like this
while read lines;
do
((for i = 0; i<=numberofelementline; i++))
do
element = ....
echo $element
done
done < test.txt
read -a line <<< $a
for i in ${!line[#]}; do echo ${rline[i]}; done
We read a file / line and store as an array. Next for each element of the array we run a for loop. This way you know the element and it's position.
You could replace all spaces to new lines and read them again with another while loop:
while read LINE; do
echo "$LINE" | tr -s ' ' '\n' | while read NUM; do
echo $NUM
done
done < test.txt
If you just want to echo them:
cat test.txt | tr ' ' '\n'
If you want to use the numbers:
while read num; do
echo $num
...
done < <( cat test.txt | tr ' ' '\n' )
Related
We need to write a script taking the input file which contains number of lines,
where in one line it has 5 delimeters ( 1|2|3|4|5).
Assume file has 3 lines like
20|30|10|40
40|50|60|70
5|3|2|1
We need to read the file line by line and check if the second delimeter value is greater than third value (i.e., 30>10). If it is true, print the whole line and as well as print all the lines where 2nd value > 3rd value.
Need anyone's help.
Thanks in advance.
Here's one approach. Read the file into a loop and for each line, split it into an array and print it if arr[1] > arr[2]:
#!/bin/bash
while read line; do
# split line on spaces and pipes
IFS='| ' read -r -a arr <<< "$line"
# echo line if second elem > third elem
if [[ ${arr[1]} -gt ${arr[2]} ]]; then
echo $line
fi
done < text
Output:
a | 30 | 20 | 40 | 50
c | 20 | 10 | 30 | 40
In A.csv, there are
1
2
3
4
How should I read this file and create variables $B and $C so that:
echo $B
echo $C
returns:
1 2 3 4
1,2,3,4
So far I am trying:
cat A.csv | while read A;
do
echo $A
done
It only returns
1
2
3
4
Assuming bash 4.x, the following is efficient, robust, and native:
# Read each line of A.csv into a separate element of the array lines
readarray -t lines <A.csv
# Generate a string B with a comma after each item in the array
printf -v B '%s,' "${lines[#]}"
# Prune the last comma from that string
B=${B%,}
# Generate a string C with a space after each item in the array
printf -v B '%s ' "${lines[#]}"
As #Cyrus said
B=$(cat A.csv)
echo $B
Will output:
1 2 3 4
Because bash will not carry the newlines if the variable is not wrapped in quotes. This is dangerous if A.csv contains any characters which might be affected by bash glob expansion, but should be fine if you are just reading simple strings.
If you are reading simple strings with no spaces in any of the elements, you can also get your desired result for $C by using:
echo $B | tr ' ' ','
This will output:
1,2,3,4
If lines in A.csv may contain bash special characters or spaces then we return to the loop.
For why I've formatted the file reading loop as I have, refer to: Looping through the content of a file in Bash?
B=''
C=''
while read -u 7 curr_line; do
if [ "$B$C" == "" ]; then
B="$curr_line"
C="$curr_line"
else
B="$B $curr_line"
C="$C,$curr_line"
fi
done 7<A.csv
echo "$B"
echo "$C"
Will construct the two variables as you desire using a loop through the file contents and should prevent against unwanted globbing and splitting.
B=$(cat A.csv)
echo $B
Output:
1 2 3 4
With quotes:
echo "$B"
Output:
1
2
3
4
I would read the file into a bash array:
mapfile -t array < A.csv
Then, with various join characters
b="${array[*]}" # space is the default
echo "$b"
c=$( IFS=","; echo "${array[*]}" )
echo "$c"
Or, you can use paste to join all the lines with a specified separator:
b=$( paste -d" " -s < A.csv )
c=$( paste -d"," -s < A.csv )
Try this :
cat A.csv | while read A;
do
printf "$A"
done
Regards!
Try This(Simpler One):
b=$(tr '\n' ' ' < file)
c=$(tr '\n' ',' < file)
You don't have to read File for that. Make sure you ran dos2unix file command. If you are running in windows(to remove \r).
Note: It will modify the file. So, make sure you copied from original file.
I'd like to rearrange a file in two columns after the nth line.
For example, say I have a file like this here:
This is a bunch
of text
that I'd like to print
as two
columns starting
at line number 7
and separated by four spaces.
Here are some
more lines so I can
demonstrate
what I'm talking about.
And I'd like to print it out like this:
This is a bunch and separated by four spaces.
of text Here are some
that I'd like to print more lines so I can
as two demonstrate
columns starting what I'm talking about.
at line number 7
How could I do that with a bash command or function?
Actually, pr can do almost exactly this:
pr --output-tabs=' 1' -2 -t tmp1
↓
This is a bunch and separated by four spaces.
of text Here are some
that I'd like to print more lines so I can
as two demonstrate
columns starting what I'm talking about.
at line number 7
-2 for two columns; -t to omit page headers; and without the --output-tabs=' 1', it'll insert a tab for every 8 spaces it added. You can also set the page width and length (if your actual files are much longer than 100 lines); check out man pr for some options.
If you're fixed upon “four spaces more than the longest line on the left,” then perhaps you might have to use something a bit more complex;
The following works with your test input, but is getting to the point where the correct answer would be, “just use Perl, already;”
#!/bin/sh
infile=${1:-tmp1}
longest=$(longest=0;
head -n $(( $( wc -l $infile | cut -d ' ' -f 1 ) / 2 )) $infile | \
while read line
do
current="$( echo $line | wc -c | cut -d ' ' -f 1 )"
if [ $current -gt $longest ]
then
echo $current
longest=$current
fi
done | tail -n 1 )
pr -t -2 -w$(( $longest * 2 + 6 )) --output-tabs=' 1' $infile
↓
This is a bunch and separated by four spa
of text Here are some
that I'd like to print more lines so I can
as two demonstrate
columns starting what I'm talking about.
at line number 7
… re-reading your question, I wonder if you meant that you were going to literally specify the nth line to the program, in which case, neither of the above will work unless that line happens to be halfway down.
Thank you chatraed and BRPocock (and your colleague). Your answers helped me think up this solution, which answers my need.
function make_cols
{
file=$1 # input file
line=$2 # line to break at
pad=$(($3-1)) # spaces between cols - 1
len=$( wc -l < $file )
max=$(( $( wc -L < <(head -$(( line - 1 )) $file ) ) + $pad ))
SAVEIFS=$IFS;IFS=$(echo -en "\n\b")
paste -d" " <( for l in $( cat <(head -$(( line - 1 )) $file ) )
do
printf "%-""$max""s\n" $l
done ) \
<(tail -$(( len - line + 1 )) $file )
IFS=$SAVEIFS
}
make_cols tmp1 7 4
Could be optimized in many ways, but does its job as requested.
Input data (configurable):
file
num of rows borrowed from file for the first column
num of spaces between columns
format.sh:
#!/bin/bash
file=$1
if [[ ! -f $file ]]; then
echo "File not found!"
exit 1
fi
spaces_col1_col2=4
rows_col1=6
rows_col2=$(($(cat $file | wc -l) - $rows_col1))
IFS=$'\n'
ar1=($(head -$rows_col1 $file))
ar2=($(tail -$rows_col2 $file))
maxlen_col1=0
for i in "${ar1[#]}"; do
if [[ $maxlen_col1 -lt ${#i} ]]; then
maxlen_col1=${#i}
fi
done
maxlen_col1=$(($maxlen_col1+$spaces_col1_col2))
if [[ $rows_col1 -lt $rows_col2 ]]; then
rows=$rows_col2
else
rows=$rows_col1
fi
ar=()
for i in $(seq 0 $(($rows-1))); do
line=$(printf "%-${maxlen_col1}s\n" ${ar1[$i]})
line="$line${ar2[$i]}"
ar+=("$line")
done
printf '%s\n' "${ar[#]}"
Output:
$ > bash format.sh myfile
This is a bunch and separated by four spaces.
of text Here are some
that I'd like to print more lines so I can
as two demonstrate
columns starting what I'm talking about.
at line number 7
$ >
This is probably pretty basic, I want to read in a occurrence file.
Then the program should find all occurrences of "CallTilEdb" in the file Hendelse.logg:
CallTilEdb 8
CallCustomer 9
CallTilEdb 4
CustomerChk 10
CustomerChk 15
CallTilEdb 16
and sum up then right column. For this case it would be 8 + 4 + 16, so the output I would want would be 28.
I'm not sure how to do this, and this is as far as I have gotten with vistid.sh:
#!/bin/bash
declare -t filename=hendelse.logg
declare -t occurance="$1"
declare -i sumTime=0
while read -r line
do
if [ "$occurance" = $(cut -f1 line) ] #line 10
then
sumTime+=$(cut -f2 line)
fi
done < "$filename"
so the execution in terminal would be
vistid.sh CallTilEdb
but the error I get now is:
/home/user/bin/vistid.sh: line 10: [: unary operator expected
You have a nice approach, but maybe you could use awk to do the same thing... quite faster!
$ awk -v par="CallTilEdb" '$1==par {sum+=$2} END {print sum+0}' hendelse.logg
28
It may look a bit weird if you haven't used awk so far, but here is what it does:
-v par="CallTilEdb" provide an argument to awk, so that we can use par as a variable in the script. You could also do -v par="$1" if you want to use a variable provided to the script as parameter.
$1==par {sum+=$2} this means: if the first field is the same as the content of the variable par, then add the second column's value into the counter sum.
END {print sum+0} this means: once you are done from processing the file, print the content of sum. The +0 makes awk print 0 in case sum was not set... that is, if nothing was found.
In case you really want to make it with bash, you can use read with two parameters, so that you don't have to make use of cut to handle the values, together with some arithmetic operations to sum the values:
#!/bin/bash
declare -t filename=hendelse.logg
declare -t occurance="$1"
declare -i sumTime=0
while read -r name value # read both values with -r for safety
do
if [ "$occurance" == "$name" ]; then # string comparison
((sumTime+=$value)) # sum
fi
done < "$filename"
echo "sum: $sumTime"
So that it works like this:
$ ./vistid.sh CallTilEdb
sum: 28
$ ./vistid.sh CustomerChk
sum: 25
first of all you need to change the way you call cut:
$( echo $line | cut -f1 )
in line 10 you miss the evaluation:
if [ "$occurance" = $( echo $line | cut -f1 ) ]
you can then sum by doing:
sumTime=$[ $sumTime + $( echo $line | cut -f2 ) ]
But you can also use a different approach and put the line values in an array, the final script will look like:
#!/bin/bash
declare -t filename=prova
declare -t occurance="$1"
declare -i sumTime=0
while read -a line
do
if [ "$occurance" = ${line[0]} ]
then
sumTime=$[ $sumtime + ${line[1]} ]
fi
done < "$filename"
echo $sumTime
For the reference,
id="CallTilEdb"
file="Hendelse.logg"
sum=$(echo "0 $(sed -n "s/^$id[^0-9]*\([0-9]*\)/\1 +/p" < "$file") p" | dc)
echo SUM: $sum
prints
SUM: 28
the sed extract numbers from a lines containing the given id, such CallTilEdb
and prints them in the format number +
the echo prepares a string such 0 8 + 16 + 4 + p what is calculation in RPN format
the dc do the calculation
another variant:
sum=$(sed -n "s/^$id[^0-9]*\([0-9]*\)/\1/p" < "$file" | paste -sd+ - | bc)
#or
sum=$(grep -oP "^$id\D*\K\d+" < "$file" | paste -sd+ - | bc)
the sed (or the grep) extracts and prints only the numbers
the paste make a string like number + number + number (-d+ is a delimiter)
the bc do the calculation
or perl
sum=$(perl -slanE '$s+=$F[1] if /^$id/}{say $s' -- -id="$id" "$file")
sum=$(ID="CallTilEdb" perl -lanE '$s+=$F[1] if /^$ENV{ID}/}{say $s' "$file")
Awk translation to script:
#!/bin/bash
declare -t filename=hendelse.logg
declare -t occurance="$1"
declare -i sumTime=0
sumtime=$(awk -v entry=$occurance '
$1==entry{time+=$NF+0}
END{print time+0}' $filename)
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