I am trying to write a script in BASH that will take between 1 and 5 command line arguments from the user and report them back in reverse numerical order to standard output. The only command I know that would work similarly to this is the sort command, but this only works for files. Is there a similar command for sorting command line arguments? Here is what I have so far.
#!/bin/bash
if [ $# -lt 1 ] || [ $# -gt 5 ];
then echo "Incorrect number of arguments!"
else
sorted=sort -rn $*
echo "SORTED: $sorted"
fi
Try:
sorted=$( printf '%s\n' "$#" | sort -rn )
printf '%s\n' "${sorted//$'\n'/ }"
You can give the sort command values from standard input. It expects every value on its own line, which you can achieve by combining echo and tr:
sorted=$(echo $* | tr ' ' '\n' | sort -rn - | tr '\n' ' ')
The last invocation of tr is only necessary if you want the result to be space-delimited again and not newline-delimited.
#!/bin/bash
if [ $# -lt 1 ] || [ $# -gt 5 ];
then echo "Incorrect number of arguments!"
else
sorted=$(echo $* | tr ' ' '\n' | sort -rn | tr '\n' ' ')
echo "SORTED: $sorted"
fi
echo $* | tr ' ' '\n' | sort -rn | tr '\n' ' '
You need to use command substitution $(...) to capture the output of a command like that.
#!/bin/bash
if [ $# -lt 1 ] || [ $# -gt 5 ]; then
echo "Incorrect number of arguments!"
else
sorted=$(for var in "$#"; do echo "$var"; done | sort -rn | tr -d '\n')
echo "SORTED: $sorted"
fi
$ ./test 1 2 3 4 5
SORTED: 5 4 3 2 1
$ ./test 5 4 3 2 1
SORTED: 5 4 3 2 1
Related
I'm trying to find all words in a file that don't exist in the dictionary. If I look for a single word the following works
b=ther; look $b | grep -i "^$b$" | ifne -n echo $b => ther
b=there; look $b | grep -i "^$b$" | ifne -n echo $b => [no output]
However if I try to run a "while read" loop
while read a; do look $a | grep -i "^$a$" | ifne -n echo "$a"; done < <(tr -s '[[:punct:][:space:]]' '\n' <lotr.txt |tr '[:upper:]' '[:lower:]')
The output seems to contain all (?) words in the file. Why doesn't this loop only output non-dictionary words?
Regarding ifne
If stdin is non-empty, ifne -n reprints stdin to stdout. From the manpage:
-n Reverse operation. Run the command if the standard input is empty
Note that if the standard input is not empty, it is passed through
ifne in this case.
strace on ifne confirms this behavior.
Alternative
Perhaps, as an alternative:
1 #!/bin/bash -e
2
3 export PATH=/bin:/sbin:/usr/bin:/usr/sbin
4
5 while read a; do
6 look "$a" | grep -qi "^$a$" || echo "$a"
7 done < <(
8 tr -s '[[:punct:][:space:]]' '\n' < lotr.txt \
9 | tr '[A-Z]' '[a-z]' \
10 | sort -u \
11 | grep .
12 )
So I need to have it say the person is not in the class. It seems like it is skipping my else statement. Is something wrong?
if [ $# == 1 ]; then
if grep "$1" /acct/common/CSCE215 | cut -d ',' -f1-3 | tr ',' ' '; then
true
else
echo "Sorry that person is not in CSCE215 this semester"
fi
else
echo "Command line arguments are not equal to 1"
echo "$#"
fi
The exit code of the piped commands is the exit code of the last one (tr in your case, which is always 0)
Use set -o pipefail option in your script to break piping if one of the commands failed.
Example:
$ echo foo | grep bar | tr o a ; echo $?
0
$ set -o pipefail ; echo foo | grep bar | tr o a ; echo $?
1
So your script could be:
set -o pipefail
if [ $# -eq 1 ]; then
if grep "$1" /acct/common/CSCE215 | cut -d ',' -f1-3 | tr ',' ' '; then
true
else
echo "Sorry that person is not in CSCE215 this semester"
fi
else
echo "Command line arguments are not equal to 1"
echo "$#"
fi
PS: Use set +o pipefail to restore the usual behavior.
#!/bin/bash
a=2
b=2
COUNTER=0
sam="abcd"
sam1="xyz"
sam2="mno"
for x in ls | grep .rpm
do
`C=rpm -qpR $x | grep -v CompressedFileNames | grep -v PayloadFilesHavePrefix | wc -l`
if [ "sam2"!="$sam1" ]
then
echo "${sam1}"
echo "${sam2}"
if [ $C -eq $a ]
then
COUNTER=$((COUNTER+1))
echo "${x}"
eval sam=$x
#eval sam1=sam | cut -d '-' -f 1
sam1=`echo "${sam}"| cut -d '-' -f 1`
if [ $COUNTER -eq $b ]
then
break
fi
fi
fi
sam2=`echo "${x}"| cut -d '-' -f 1`
done
This is the output I am getting:
xyz
mno
comps-4ES-0.20050107.x86_64.rpm
comps
comps
comps-4ES-0.20050525.x86_64.rpm
My question is: why is the if condition returning true despite sam1 and sam2 being equal? I have checked for non-equality.
Response is the same even if I use
if [ $C -eq $a ] && [ "$sam2" != " $sam1" ]
As Ansgar Wiechers pointed out, you're missing a "$" in front of the sam2 variable. That way, you're comparing the literal string "sam2" with the string value of $sam1 (which initially is set to "xyz"). What you want to do is compare the string values of both variables:
if [ "$sam2" != "$sam1" ]
Regarding $C, you should only include the commands to be evaluated inside backticks, not the evaluation itself. This is called a command substitution - a subshell is created in which the commands are executed, and the backtick expression is substituted by the computed value. The line should look like this:
C=`rpm -qpR $x | grep -v CompressedFileNames | grep -v PayloadFilesHavePrefix | wc -l`
Your for loop also needs a command substitution: for x in ls | grep .rpm makes it look as if you're piping the output of a for command into grep. What you want to do is iterate over the ls | grep part, which you can do with the following command substitution:
for x in `ls | grep .rpm`
Hi Guys Got the solution:
#!/bin/bash
read -p "enter dep number" a
read -p "enter no of rpms" b
COUNTER=0
sam="abcd"
sam1="xyz"
sam2="mno"
for x in `ls | grep .rpm`
do
C=`rpm -qpR $x |grep -v CompressedFileNames | grep -v PayloadFilesHavePrefix | wc -l`
# echo "${C}:c"
if [ $C -eq $a ] && [ "$sam2" != "$sam1" ]
then
COUNTER=$((COUNTER+1))
# echo "${COUNTER}:counter"
# echo "${x}"
eval sam=$x
#eval sam1=sam | cut -d '-' -f 1
sam1=`echo "${sam}"| cut -d '-' -f 1`
if [ $COUNTER -eq $b ]
then
break
fi
fi
sam2=`echo "${x}"| cut -d '-' -f 1`
#echo "${sam2}"
#echo "${sam1}"
done
I have a string like 1001.2001.3001.5001.6001 or 1001-2001-3001-5001-6001. How to extract the 4th string i.e., 5001, add a value like 121 to it and put it back in the same string. The output should be like 1001.2001.3001.5122.6001 or 1001-2001-3001-5122-6001. I have to achieve this in Linux bash scripting.
Try this
#!/bin/bash
str=$1
if [[ $(echo $str | grep '\.' | wc -l) == 1 ]]
then
str1=$(echo $str | cut -d '.' -f 1,2,3)
str2=$(echo $str | cut -d '.' -f 4 | awk {'print $1+121'})
str3=$(echo $str | cut -d '.' -f 5)
echo $str1.$str2.$str3
elif [[ $(echo $str | grep - | wc -l) == 1 ]]
then
str1=$(echo $str | cut -d '-' -f 1,2,3)
str2=$(echo $str | cut -d '-' -f 4 | awk {'print $1+121'})
str3=$(echo $str | cut -d '-' -f 5)
echo $str1-$str2-$str3
else
echo "do nothing"
fi
Pass a string as parameter
No pipes, no forks, no cutting, no awking, just plain POSIX shell:
$ s=1001.2001.3001.5001.6001
$ oldIFS=$IFS
$ IFS=.-
$ set -- $s
$ case $s in
> (*.*) echo "$1.$2.$3.$(($4 + 121)).$5";;
> (*-*) echo "$1-$2-$3-$(($4 + 121))-$5";;
> esac
1001.2001.3001.5122.6001
$ IFS=$oldIFS
One liner
value=121 ; str='1001.2001.3001.5001.6001' ; token="$(echo "$str" | cut -f 4 -d '.')" ; newtoken=$(( $token + $value )) ; newstr="$(echo "$str" | sed -e "s/$token/$newtoken/g" | tr '.' '-')" ; echo "$newstr"
Breakdown:
value=121 # <- Increment
str='1001.2001.3001.5001.6001' # <- Initial String
token="$(echo "$str" | cut -f 4 -d '.')" # <- Extract the 4th field with . sep
newtoken=$(( $token + $value )) # <- Add value and save to $newtoken
newstr="$(echo "$str" \
| sed -e "s/$token/$newtoken/g" \
| tr '.' '-')" # <- Replace 4th field with $newtoken
# and translate "." to "-"
echo "$newstr" # <- Echo new string
Works in:
Bash
sh
FreeBSD
Busybox
Using out of the box tools
If the field separator can either be . or -, then do something like
echo "1001.2001.3001.5001.6001" | awk 'BEGIN{FS="[.-]";OFS="-"}{$4+=121}1'
1001-2001-3001-5122-6001
However, if you need to match the regex FS or field separator with OFS then you need to have gawk installed
echo "1001.2001.3001.5001.6001" |
gawk 'BEGIN{FS="[.-]"}{split($0,a,FS,seps)}{$4+=121;OFS=seps[1]}1'
1001.2001.3001.5122.6001
Though resetting the argument list with the values is probably the preferred way, or by setting IFS to the delimiter and reading the values into an array and adding the desired value to the array index at issue, you can also do it with a simple loop to look for the delimiters and continually skipping characters until the desired segment is found (4 in you case -- when the delimiter count is 3). Then simply appending the digit at each array index until your next delimiter is found will give you the base value. Simply adding your desired 121 to the completed number completes the script, e.g.
#!/bin/bash
str=${1:-"1001.2001.3001.5001.6001"} ## string
ele=${2:-4} ## element to add value to [1, 2, 3, ...]
add=${3:-121} ## value to add to element
cnt=0 ## flag to track delimiters found
num=
## for each character in str
for ((i = 0; i < ${#str}; i++))
do
if [ "${str:$i:1}" = '.' -o "${str:$i:1}" = '-' ] ## is it '.' or '-'
then
(( cnt++ )) ## increment count
(( cnt == ele )) && break ## if equal to ele, break
## check each char is a valid digit 0-9
elif [ "0" -le "${str:$i:1}" -a "${str:$4i:1}" -le "9" ]
then
(( cnt == (ele - 1) )) || continue ## it not one of interest, continue
num="$num${str:$i:1}" ## append digit to num
fi
done
((num += add)) ## add the amount to num
printf "num: %d\n" $num ## print results
Example Use/Output
$ bash parsenum.sh
num: 5122
$ bash parsenum.sh "1001.2001.3001.5001.6001" 2
num: 2122
$ bash parsenum.sh "1001.2001.3001.5001.6001" 2 221
num: 2222
Look things over and let me know if you have any questions.
I am trying a simple shell script like the following:
#!/bin/bash
up_cap=$( cat result.txt | cut -d ":" -f 6,7 | sort -n | cut -d " " -f 2 | sort -n)
down_cap=$( cat result.txt | cut -d : -f 6,7 | sort -n | cut -d " " -f 6| sort -n)
for value in "${down_cap[#]}";do
if [ $value > 80000 ]; then
cat result.txt | grep -B 1 "$value"
fi
done
echo " All done, exiting"
when I execute the above script as ./script.sh, I get the error:
./script.sh: line 5: [: too many arguments
All done, exiting
I have googled enough, and still not able to rectify this.
You want
if [ "$value" -gt 80000 ]; then
You use -gt for checking if A is bigger than B, not >. The quotation marks I merely added to prevent the script from failing in case $value is empty.
Try to declare variable $value explicitly:
declare -i value
So, with the dominikh's and mine additions the code should look like this:
#!/bin/bash
up_cap=$( cat result.txt | cut -d ":" -f 6,7 | sort -n | cut -d " " -f 2 | sort -n)
down_cap=$( cat result.txt | cut -d : -f 6,7 | sort -n | cut -d " " -f 6| sort -n)
for value in "${down_cap[#]}";do
declare -i value
if [ $value -gt 80000 ]; then
cat result.txt | grep -B 1 "$value"
fi
done
echo " All done, exiting"