If I run:
s.sh A B=" " C
s.sh
#!/bin/bash
count() {
echo $#
echo "$1" "$2" "$3"
}
count "$#"
I get following output:
3
A B= C
which is the expected one. Good!
But if I run:
s2.sh -f file.txt
s2.sh
#!/bin/bash
count() {
echo $#
echo "$1" "$2" "$3"
}
while read line || [[ -n "$line" ]]
do
echo -e "\nLine: $line"
count $line
done < $2
file.txt
A B=" " C
I don't get a similar output. It is:
Line: A B=" " C
4
A B=" "
Actual: 4 arguments
Expected: 3 arguments (the same as the ones mentioned in the example with the arguments provided through the command line)
I've also tried to use the following lines in file.txt:
A B=' ' C
A B=\" \" C
A B= C
A B=\ \ \ \ \ \ \ C
and to use count "$line", but I couldn't achieve the expected behavior.
How can I read those arguments from file?
To process quotes and other metacharacters in the input line, you need to use eval:
eval "count $line"
Related
I have an issue with the echo in the for loop, as I want to count string chars especailly for "*" it but it prints all the files in current directory.
clearvar() {
int=0
str=0
uniqchar=0
}
countstring(){
for c in $(echo "${1}" | fold -w1); do
echo "$c"
if [[ $c == [0-9] ]];then
int=$(( $int + 1 ))
elif [[ $c == [a-Z] ]];then
str=$(( $str + 1 ))
else
uniqchar=$(( $uniqchar + 1 ))
fi
done
}
while [ $# -gt 0 ];do
echo "Argument input: $1"
read -p "Input: " string
rmws=$(echo $string | tr -d " ")
mashed=$rmws$1
countstring $mashed
echo -e "int: $int\nstr: $str\nuniquechar: $uniqchar\nWhole string: $mashed"
clearvar
shift
done
Example output:
Argument input: io1
Input: fj^*23
f
j
^
file1
file2
file3
2
3
i
o
1
int: 3
str: 4
uniquechar: 4
Whole string: fj^*2wio1
it interprets as echo * instead of echo "*".
so I expect it to not print out the file names.
rmws=$(echo $string | tr -d " ")
If string=* this just executes echo * and expands the *.
The same happens in:
countstring $mashed
Both these expansions are unquoted. Quote them in double quotes. As a rule of a thumb - always use double quotes.
Also the same happens in the for loop:
for c in $(echo "${1}" | fold -w1)
the expansion, as elsewhere, is unquoted, so * expands. You have to quote. That's why the for i in $(..) is considered bad style - because such bugs happen. You can't do for i in "$(...)" because then you would iterate over one element. To iterate over lines or elements in a stream use a while IFS= read -r loop. You can print every character on each separate line with ex. sed 's/./&\n/g' and iterate over lines, or use bash extension read -n1 to read one character.
while IFS= read -r -n1 c; do
..
done <<<"$1"
The <<<"$1" is a bash's "here string".
You don't need $ in arithmetic expansion. Just:
int=$(( int + 1 ))
str=$(( str + 1 ))
uniqchar=$(( uniqchar + 1 ))
or in bash you can even do:
(( int++ ))
# and so on
Your script could become:
clearvar() {
int=0
str=0
uniqchar=0
}
countstring(){
while IFS= read -r -n1 c; do
echo "$c"
if [[ $c == [0-9] ]];then
(( int++ ))
elif [[ $c == [a-Z] ]];then
(( str++ ))
else
(( uniqchar++ ))
fi
done <<<"$1"
}
while [ $# -gt 0 ]; do
echo "Argument input: $1"
read -p "Input: " string
rmws="$(echo "$string" | tr -d " ")"
mashed="$rmws$1"
countstring "$mashed"
echo "int: $int"
echo "str: $str"
echo "uniquechar: $uniqchar"
echo "Whole string: $mashed"
clearvar
shift
done
Notes:
echo has portability issues. Prefer to use printf instead.
I prefer while (($#)); do in place of while [ $# -eq 0 ]; do.
PS. I would use tr:
countstring() {
printf "%s" "$1" | tr -cd '[0-9]' | wc -c
printf "%s" "$1" | tr -cd '[a-zA-Z]' | wc -c
printf "%s" "$1" | tr -d '[0-9a-zA-Z]' | wc -c
}
I'm totally new to writing code with shell script.
This is my code:
#!/bin/bash
echo -n "Output to $2 "
# set counter
count=1
# zap output file
> $2
# Loop
while [ $count -le $1 ]
do
# generate some random text
randomnumber=`od -A n -t d -N 1 /dev/urandom`
randomtext=`cat /dev/urandom | tr -cd "[:alnum:]" | head -c $randomnumber`
# generate a random number
randomnumber=`od -A n -t d -N 1 /dev/urandom`
# output to file
echo "$count,$randomtext,$randomnumber" | sed -e "s: *::g" >> $2
# increment counter
count=$(($count + 1))
if [ $(($count % 500)) -eq 0 ]
then
echo -n "." fi
done
echo " Output complete"
And this is my error:
Line 2: ambiguous redirect and Line 14: unary operator expected.
Can anybody help me to understand why I having that error?
As #GlennJackman points out, the lines are not matching the code, hence I am guessing the following:
The ambiguous redirection is on line 6: To truncate a file, you
should use truncate -s0 $2
For the unary operator error, I bet on line 21: either put a linefeed
or a semicolon ; before fi
Try the following:
#!/bin/bash
echo -n "Output to $2 "
# set counter
count=1
# zap output file
truncate -s0 $2
# Loop
while [ $count -le $1 ]
do
# generate some random text
randomnumber=`od -A n -t d -N 1 /dev/urandom`
randomtext=`cat /dev/urandom | tr -cd "[:alnum:]" | head -c $randomnumber`
# generate a random number
randomnumber=`od -A n -t d -N 1 /dev/urandom`
# output to file
echo "$count,$randomtext,$randomnumber" | sed -e "s: *::g" >> $2
# increment counter
count=$(($count + 1))
if [ $(($count % 500)) -eq 0 ]
then
echo -n "."
fi
done
echo " Output complete"
I have a SQL*Plus output written into a text file in the following format:
3459906| |2|X1|WAS1| Output1
334596| |2|X1|WAS2| Output1
3495792| |1|X1|WAS1| Output1
687954| |1|X1|WAS2| Output1
I need a shell script to fetch the counts which were at the beginning based on the text after the counts.
For example, If the Text is like |2|X1|WAS1| , then 3459906 should be passed on to a variable x1was12 and if the text is like |2|X1|WAS2| , then 334596 should be passed on to a variable x1was22.
I tried writing a for loop and if condition to pass on the counts, but was unsuccessful:
export filename1='file1.dat'
while read -r line ; do
if [[ grep -i "*|2|X1|WAS1| Output1*" | wc -l -eq 0 ]] ; then
export xwas12=sed -n ${line}p $filename1 | \
sed 's/[^0-9]*//g' | sed 's/..$//'
elif [[ grep -i "*|2|X1|WAS2| Output1*" | wc -l -eq 0 ]] ; then
export x1was22=sed -n ${line}p $filename1 | \
sed 's/[^0-9]*//g' | sed 's/..$//'
elif [[ grep -i "*|1|X1|WAS1| Output1*" | wc -l -eq 0 ]] ; then
export x1was11=sed -n ${line}p $filename1 | \
sed 's/[^0-9]*//g' | sed 's/..$//'
elif [[ grep -i "*|1|X1|WAS2| Output1*" | wc -l -eq 0 ]]
export x1was21=sed -n ${line}p $filename1 | \
sed 's/[^0-9]*//g' | sed 's/..$//'
fi
done < "$filename1"
echo '$x1was12' > output.txt
echo '$x1was22' >> output.txt
echo '$x1was11' >> output.txt
echo '$x1was21' >> output.txt
What I was trying to do was:
Go to the first line in the file
-> Search for the text and if found then assign the sed output to the variable
Then go to the second line of the file
-> Search for the texts in the if commands and assign the sed output to another variable.
same goes for other
while IFS='|' read -r count _ n x was _; do
# remove spaces from all variables
count=${count// /}; n=${n// /}; x=${x// /}; was=${was// /}
varname="${x}${was}${n}"
printf -v "${varname,,}" %s "$count"
done <<'EOF'
3459906| |2|X1|WAS1| Output1
334596| |2|X1|WAS2| Output1
3495792| |1|X1|WAS1| Output1
687954| |1|X1|WAS2| Output1
EOF
With the above executed:
$ echo "$x1was12"
3459906
Of course, the redirection from a heredoc could be replaced with a redirection from a file as well.
How does this work? Let's break it down:
Every time IFS='|' read -r count _ n x was _ is run, it reads a single line, separating it by |s, putting the first column into count, discarding the second by assigning it to _, reading the third into n, the fourth into x, the fifth into was, and the sixth and all following content into _. This practice is discussed in detail in BashFAQ #1.
count=${count// /} is a parameter expansion which prunes spaces from the variable count, by replacing all such spaces with empty strings. See also BashFAQ #100.
"${varname,,}" is another parameter expansion, this one converting a variable's contents to all-lowercase. (This requires bash 4.0; in prior versions, consider "$(tr '[:upper:]' '[:lower:]' <<<"$varname") as a less-efficient alternative).
printf -v "$varname" %s "value" is a mechanism for doing an indirect assignment to the variable named in the variable varname.
If not for the variable names, the whole thing could be done with two commands:
cut -d '|' -f1 file1.dat | tr -d ' ' > output.txt
The variable names make it more interesting. Two bash methods follow, plus a POSIX method...
The following bash code ought to do what the OP's sample code was
meant to do:
declare $(while IFS='|' read a b c d e f ; do
echo $a 1>&2 ; echo x1${e,,}$c=${a/ /}
done < file1.dat 2> output.txt )
Notes:
The bash shell is needed for ${e,,}, (turns "WAS" into "was"), and $a/ /} , (removes a leading space that might be in
$a), and declare.
The while loop parses file1.dat and outputs a bunch of variable assignments. Without the declare this code:
while IFS='|' read a b c d e f ; do
echo x1${e,,}$c=${a/ /} ;
done < file1.dat
Outputs:
x1was12=3459906
x1was22=334596
x1was11=3495792
x1was21=687954
The while loop outputs to two separate streams: stdout (for the declare), and stderr (using the 1>&2 and 2> redirects for
output.txt).
Using bash associative arrays:
declare -A x1was="( $(while IFS='|' read a b c d e f ; do
echo $a 1>&2 ; echo [${e/WAS/}$c]=${a/ /}
done < file1.dat 2> output.txt ) )"
In which case the variable names require brackets:
echo ${x1was[21]}
687954
POSIX shell code (tested using dash):
eval $(while IFS='|' read a b c d e f ; do
echo $a 1>&2; echo x1$(echo $e | tr '[A-Z]' '[a-z]')$c=$(echo $a)
done < file1.dat 2> output.txt )
eval should not be used if there's any doubt about what's in file1.dat. The above code assumes the data in file1.dat is
uniformly dependable.
Using bash shell:
I am trying to read a file line by line.
and every line contains two meaning full file names delimited by "``"
file:1 image_config.txt
bbbbb.mp4``thumb/hashdata.gif
bbbbb.mp4``thumb/hashdata2.gif
Shell Script
#!/bin/bash
filename="image_config.txt"
while IFS='' read -r line || [[ -n "$line" ]]; do
IFS='``' read -r -a array <<< "$line"
if [ "$line" = "" ]; then
echo lineempty
else
file=${array[0]}
hash=${array[2]}
echo $file$hash;
output=$(ffmpeg -v warning -ss 2 -t 0.8 -i $file -vf scale=200:-1 -gifflags +transdiff -y $hash);
echo $output;
# echo ${array[0]}${array[1]}${array[2]}
fi;
done < "$filename"
first time executed successfully but when loop executes second time.
variable file lost bbbbb from bbbbb.mp4
and following output comes out
Output :
user#domain [~/public_html/Videos]$ sh imager.sh
bbbbb.mp4thumb/hashdata.gif
.mp4thumb/hashdata2.gif
.mp4: No such file or directory
lineempty
Please check out Bash FAQ 89 - I'm using a loop which runs once per line of input but it only seems to run once; everything after the first line is ignored? which seems to be helpful in your case.
Aside:
There is no point in using the same character twice in IFS.
IFS=\`
Is enough.
Check out this:
var='abc``def'
IFS=\`\` read -ra arr <<< "$var"
printf '<%s>\n' "${arr[#]}"
Output:
<abc>
<>
<def>
As you can see, arr[0] is abc, arr[1] is empty and arr[2] is def, and not arr[0] is abc and arr[1] is def as one might expect.
Taken from the IFS wiki of Greycat and Lhunath Bash Guide :
The IFS variable is used in shells (Bourne, POSIX, ksh, bash) as the input field separator (or internal field separator). Essentially, it is a string of special characters which are to be treated as delimiters between words/fields when splitting a line of input.
Here is how you could do differently, avoiding a read in the read:
#!/bin/bash
filename="image_config.txt"
while IFS='' read -r line || [[ -n "$line" ]]; do
if [ "$line" = "" ]; then
echo lineempty
else
file=$( echo ${line} | awk -F \` ' { print $1 } ' )
hash=$( echo ${line} | awk -F \` ' { print $3 } ' )
echo $file$hash;
output=$(ffmpeg -v warning -ss 2 -t 0.8 -i $file -vf scale=200:-1 -gifflags +transdiff -y $hash);
echo $output;
fi;
done < "$filename"
I have to write a script, which will take all arguments and print them in reverse.
I've made a solution, but find it very bad. Do you have a smarter idea?
#!/bin/sh
> tekst.txt
for i in $*
do
echo $i | cat - tekst.txt > temp && mv temp tekst.txt
done
cat tekst.txt
Could do this
for (( i=$#;i>0;i-- ));do
echo "${!i}"
done
This uses the below
c style for loop
Parameter indirect expansion
(${!i}towards the bottom of the page)
And $# which is the number of arguments to the script
you can use this one liner:
echo $# | tr ' ' '\n' | tac | tr '\n' ' '
bash:
#!/bin/bash
for i in "$#"; do
echo "$i"
done | tac
call this script like:
./reverse 1 2 3 4
it will print:
4
3
2
1
Portably and POSIXly, without arrays and working with spaces and newlines:
Reverse the positional parameters:
flag=''; c=1; for a in "$#"; do set -- "$a" ${flag-"$#"}; unset flag; done
Print them:
printf '<%s>' "$#"; echo
Reversing a simple string, by spaces
Simply:
#!/bin/sh
o=
for i;do
o="$i $o"
done
echo "$o"
will work as
./rev.sh 1 2 3 4
4 3 2 1
Or
./rev.sh world! Hello
Hello world!
If you need to output one line by argument
Just replace echo by printf "%s\n":
#!/bin/sh
o=
for i;do
o="$i $o"
done
printf "%s\n" $o
Reversing an array of strings
If your argument could contain spaces, you could use bash arrays:
#!/bin/bash
declare -a o=()
for i;do
o=("$i" "${o[#]}")
done
printf "%s\n" "${o[#]}"
Sample:
./rev.sh "Hello world" print will this
this
will
print
Hello world
As a function (If you're ok to play with eval.
But eval is evil!!
rev() { eval "set --" $(seq -f '"${%g}"' $# -1 1);printf '%s\n' "$#";}
Then
rev Hello\ world print will this
this
will
print
Hello world