I want to get the size of the directory's content. If I use the command line I can get like this:
ls -l | head -n 1 | awk '{ print $2 }'
So the output is the size of the directory's content:
16816
But I want to do this in a bash script:
x="ls -l DBw | head -n 1 | awk '{ print $2 }'"
while sleep 1; do
y=$(eval "$x");
echo $y
done
But the output of this script is the full line:
Total 16816
Why is this happening and how can I get just the second word?
x="ls -l DBw | head -n 1 | awk '{ print $2 }'"
It's happening because $2 is inside double quotes and so it's interpreted immediately. You could escape it with \$2, but better yet:
Don't store code in variables. Use a function.
x() {
ls -l DBw | head -n 1 | awk '{ print $2 }'
}
Then you can call x many times.
while sleep 1; do
x
done
That said, it's better not to parse the output of ls in the first place. Use du to compute the size of a directory:
$ du -sh /dir
1.3M /dir
$ du -sh /dir | cut -f1
1.3M
Related
I am trying to get the total disk usage of my machine. Below is the script code:
#!/bin/sh
totalUsage=0
diskUse(){
df -H | grep -vE '^Filesystem|cdrom' | awk '{ print $5 " " $1 }' | while read output;
do
diskUsage=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
totalUsage=$((totalUsage+diskUsage))
done
}
diskUse
echo $totalUsage
While totalUsage is a global variable, I have tried to sum the individual disk usage to totalUsage in the line:
totalUsage=$((totalUsage+diskUsage))
An echo of totalUsage between do and done shows the correct value,
but when I try to echo it after my call diskUse, it stills prints a 0
Can you please help me, what is wrong here?
The variable totalUsage in a sub-shell doesn't change the value in the parent shell.
Since you tagged bash, you can use here string to modify your loop:
#!/bin/bash
totalUsage=0
diskUse(){
while read output;
do
diskUsage=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
totalUsage=$((totalUsage+diskUsage))
done <<<"$(df -H | grep -vE '^Filesystem|cdrom' | awk '{ print $5 " " $1 }')"
}
diskUse
echo $totalUsage
I suggest to insert
shopt -s lastpipe
as new line after
#!/bin/bash
From man bash:
lastpipe: If set, and job control is not active, the shell runs the last command of a pipeline not executed in the background in the current shell environment.
how can i make a loop for users of server using shell script
i wrote this code ..
#!/bin/bash
b=`awk -F: '{ print $1 }' /etc/passwd | sort`
for $b in /home/$b/ /home/$b/ /home/$b/
echo "$b"
done
i want to loop all users and show its
the users like in file
/etc/passwd
like :
root,admin,cpanel,adm,mysql,user1,user2,user3,user4,user5
i want the output :
/home/adm
/home/root
/home/admin
/home/mysql
/home/user1
/home/user2
and thanks
To print /home/ before each user name:
$ awk -F: ' { print "/home/"$1 }' /etc/passwd | sort
/home/avahi
/home/backup
/home/bin
/home/clamav
/home/colord
/home/daemon
[...snip...]
If you want actual home directories, you can find them in field 6:
$ awk -F: ' { print $6 }' /etc/passwd | sort
/dev/null
/home/john1024
/nonexistent
/root
You can also access the sixth field using cut:
cut -d: -f6 /etc/passwd | sort
Printing multiple directories
As per the revised question in the comments:
$ awk -F: ' { p="/home/"$1; printf "%s\n%s\n%s\n",p"/www",p"/ftp",p"/etc" }' /etc/passwd | sort
/home/avahi/etc
/home/avahi/ftp
/home/avahi/www
/home/backup/etc
/home/backup/ftp
/home/backup/www
[...snip...]
My bash script is:
output=$(curl -s http://www.espncricinfo.com/england-v-south-africa-2012/engine/current/match/534225.html | sed -nr 's/.*<title>(.*?)<\/title>.*/\1/p')
score=echo"$output" | awk '{print $1}'
echo $score
The above script prints just a newline in my console whereas my required output is
$ curl -s http://www.espncricinfo.com/england-v-south-africa-2012/engine/current/match/534225.html | sed -nr 's/.*<title>(.*
?)<\/title>.*/\1/p' | awk '{print $1}'
SA
So, why am I not getting the output from my bash script whereas it works fine in terminal am I using echo"$output" in the wrong way.
#!/bin/bash
output=$(curl -s http://www.espncricinfo.com/england-v-south-africa-2012/engine/current/match/534225.html | sed -nr 's/.*<title>(.*?)<\/title>.*/\1/p')
score=$( echo "$output" | awk '{ print $1 }' )
echo "$score"
Score variable was probably empty, since your syntax was wrong.
At the moment here is what im doing
ret=$(ls -la | awk '{print $3 " " $9}')
usr=$(echo $ret | awk '{print $1}')
fil=$(echo $ret | awk '{print $2}')
The problem is that im not running an ls im running a command that takes time, so you can understand the logic.
Is there a way I can set the return value to set two external values, so something such as
ls -la | awk -r usr=x -r fil=y '{x=$3; y=$9}'
This way the command will be run once and i can minimize it to one line
It's not pretty, but if you really need to do this in one line you can use awk/bash's advanced meta-programming capabilities :)
eval $(ls -la | awk '{usr = $3 " " usr;fil = $9 " " fil} END{print "usr=\""usr"\";fil=\""fil"\""}')
To print:
echo -e $usr
echo -e $fil
Personally, I'd stick with what you have - it's much more readable and performance overhead is tiny compared to the above:
$time <three line approach>
real 0m0.017s
user 0m0.006s
sys 0m0.011s
$time <one line approach>
real 0m0.009s
user 0m0.004s
sys 0m0.007s
A workaround using read
usr=""
fil=""
while read u f; do usr="$usr\n$u"; fil="$fil\n$f"; done < <(ls -la | awk '{print $3 " " $9}')
For performance issue you could use <<<, but avoid it if the returned text is large:
while read u f; do usr="$usr\n$u"; fil="$fil\n$f"; done <<< $(ls -la | awk '{print $3 " " $9}')
A more portable way inspired from #WilliamPursell's answer:
$ usr=""
$ fil=""
$ while read u f; do usr="$usr\n$u"; fil="$fil\n$f"; done << EOF
> $(ls -la | awk '{print $3 " " $9}')
> EOF
What you want to do is capture the output of ls or any other command and then process it later.
ls=$(ls -l)
first=$(echo $ls | awk '{print $1}')
second=$(echo $ls | awk '{print $2}')
Using bash v4 associative array:
unset FILES
declare -A FILES
FILES=( ls -la | awk '{print $9 " " $3}' )
Print the list of owner & file:
for fil in ${!FILES[#]}
do
usr=${FILES["$fil"]}
echo -e "$usr" "\t" "$fil"
done
My apologies, I cannot test on my computer because my bash v3.2 does not support associative array :-(.
Please, report any issue...
The accepted answer uses process substitution, which is a bashism that only works on certain platforms. A more portable solution is to use a heredoc:
read u f << EOF
$( ls ... )
EOF
It is tempting to try:
ls ... | read u f
but the read then runs in a subshell. A common technique is:
ls ... | { read u f; # use $u and $f here; }
but to make the variables available in the remainder of the script, the interpolated heredoc is the most portable approach. Note that it requires the shell to read all of the output of the program into memory, so is not suitable if the output is expected to be large or if the process is long running.
You could use a bash array or the positional parameters as temporary holding place:
ret_ary=( $(command | awk '{print $3, $9}') )
usr=${ret_ary[0]}
fil=${ret_ary[1]}
set -- $(command | awk '{print $3, $9}')
usr=$1
fil=$2
Is there a way to get the integer that wc returns in bash?
Basically I want to write the line numbers and word counts to the screen after the file name.
output: filename linecount wordcount
Here is what I have so far:
files=\`ls`
for f in $files;
do
if [ ! -d $f ] #only print out information about files !directories
then
# some way of getting the wc integers into shell variables and then printing them
echo "$f $lines $words"
fi
done
Most simple answer ever:
wc < filename
Just:
wc -l < file_name
will do the job. But this output includes prefixed whitespace as wc right-aligns the number.
You can use the cut command to get just the first word of wc's output (which is the line or word count):
lines=`wc -l $f | cut -f1 -d' '`
words=`wc -w $f | cut -f1 -d' '`
wc $file | awk {'print "$4" "$2" "$1"'}
Adjust as necessary for your layout.
It's also nicer to use positive logic ("is a file") over negative ("not a directory")
[ -f $file ] && wc $file | awk {'print "$4" "$2" "$1"'}
Sometimes wc outputs in different formats in different platforms. For example:
In OS X:
$ echo aa | wc -l
1
In Centos:
$ echo aa | wc -l
1
So using only cut may not retrieve the number. Instead try tr to delete space characters:
$ echo aa | wc -l | tr -d ' '
The accepted/popular answers do not work on OSX.
Any of the following should be portable on bsd and linux.
wc -l < "$f" | tr -d ' '
OR
wc -l "$f" | tr -s ' ' | cut -d ' ' -f 2
OR
wc -l "$f" | awk '{print $1}'
If you redirect the filename into wc it omits the filename on output.
Bash:
read lines words characters <<< $(wc < filename)
or
read lines words characters <<EOF
$(wc < filename)
EOF
Instead of using for to iterate over the output of ls, do this:
for f in *
which will work if there are filenames that include spaces.
If you can't use globbing, you should pipe into a while read loop:
find ... | while read -r f
or use process substitution
while read -r f
do
something
done < <(find ...)
If the file is small you can afford calling wc twice, and use something like the following, which avoids piping into an extra process:
lines=$((`wc -l "$f"`))
words=$((`wc -w "$f"`))
The $((...)) is the Arithmetic Expansion of bash. It removes any whitespace from the output of wc in this case.
This solution makes more sense if you need either the linecount or the wordcount.
How about with sed?
wc -l /path/to/file.ext | sed 's/ *\([0-9]* \).*/\1/'
typeset -i a=$(wc -l fileName.dat | xargs echo | cut -d' ' -f1)
Try this for numeric result:
nlines=$( wc -l < $myfile )
Something like this may help:
#!/bin/bash
printf '%-10s %-10s %-10s\n' 'File' 'Lines' 'Words'
for fname in file_name_pattern*; {
[[ -d $fname ]] && continue
lines=0
words=()
while read -r line; do
((lines++))
words+=($line)
done < "$fname"
printf '%-10s %-10s %-10s\n' "$fname" "$lines" "${#words[#]}"
}
To (1) run wc once, and (2) not assign any superfluous variables, use
read lines words <<< $(wc < $f | awk '{ print $1, $2 }')
Full code:
for f in *
do
if [ ! -d $f ]
then
read lines words <<< $(wc < $f | awk '{ print $1, $2 }')
echo "$f $lines $words"
fi
done
Example output:
$ find . -maxdepth 1 -type f -exec wc {} \; # without formatting
1 2 27 ./CNAME
21 169 1065 ./LICENSE
33 130 961 ./README.md
86 215 2997 ./404.html
71 168 2579 ./index.html
21 21 478 ./sitemap.xml
$ # the above code
404.html 86 215
CNAME 1 2
index.html 71 168
LICENSE 21 169
README.md 33 130
sitemap.xml 21 21
Solutions proposed in the answered question doesn't work for Darwin kernels.
Please, consider following solutions that work for all UNIX systems:
print exactly the number of lines of a file:
wc -l < file.txt | xargs
print exactly the number of characters of a file:
wc -m < file.txt | xargs
print exactly the number of bytes of a file:
wc -c < file.txt | xargs
print exactly the number of words of a file:
wc -w < file.txt | xargs
There is a great solution with examples on stackoverflow here
I will copy the simplest solution here:
FOO="bar"
echo -n "$FOO" | wc -l | bc # "3"
Maybe these pages should be merged?
Try this:
wc `ls` | awk '{ LINE += $1; WC += $2 } END { print "lines: " LINE " words: " WC }'
It creates a line count, and word count (LINE and WC), and increase them with the values extracted from wc (using $1 for the first column's value and $2 for the second) and finally prints the results.
"Basically I want to write the line numbers and word counts to the screen after the file name."
answer=(`wc $f`)
echo -e"${answer[3]}
lines: ${answer[0]}
words: ${answer[1]}
bytes: ${answer[2]}"
Outputs :
myfile.txt
lines: 10
words: 20
bytes: 120
files=`ls`
echo "$files" | wc -l | perl -pe "s#^\s+##"
You have to use input redirection for wc:
number_of_lines=$(wc -l <myfile.txt)
respectively in your context
echo "$f $(wc -l <"$f") $(wc -w <"$f")"