I have a txt file with blow format:
66.57.21 - john
88.43.23 - albert
10.10.11 - smith
I wanna to execute "connect.py 66.57.21 john" for each line and I wrote this bash script:
#!/bin/bash
while read LINE; do
awk -v number = "$LINE" '$1'
awk -v name = "$LINE" '$3'
connect.py $name $number
done < "$1"
but the bash script didn't work
What is the problem
#!/usr/bin/env bash
while read -r number _ name; do
connect.py "$name" "$number"
done < "$1"
If you are wanting to use awk, here is one way to do it:
awk -F" " '{system("connect.py " $3 " " $1)}' input.txt
The -F" " splits each line of input on spaces
$1 is the first word in the array (number in the original question)
$3 is he third word in the array (name in the original question)
wrapping "connect.py " $3 " " $1 in system() causes the shell to execute the command after the substitutions have been made
ie: connect.py john 66.57.21
I'm relatively new to bash scripting and I would like someone to explain this properly, thank you. Here is my code:
#! /bin/bash
echo "first arg: $1"
echo "first arg: $2"
var="$( grep -rnw $1 -e $2 | cut -d ":" -f1 )"
var2=$( grep -rnw $1 -e $2 | cut -d ":" -f1 | awk '{print substr($0,length,1)}')
echo "$var"
echo "$var2"
The problem I have is with the output, the script I'm trying to write is a c++ function searcher, so upon launching my script I have 2 arguments, one for the directory and the second one as the function name. This is how my output looks like:
first arg: Projekt
first arg: iseven
Projekt/AX/include/ax.h
Projekt/AX/src/ax.cpp
h
p
Now my question is: how do can I save the line by line output as a variable, so that later on I can use var as a path, or to use var2 as a character to compare. My plan was to use IF() statements to determine the type, idea: IF(last_char == p){echo:"something"}What I've tried was this question: Capturing multiple line output into a Bash variable and then giving it an array. So my code looked like: "${var[0]}". Please explain how can I use my line output later on, as variables.
I'd use readarray to populate an array variable just in case there's spaces in your command's output that shouldn't be used as field separators that would end up messing up foo=( ... ). And you can use shell parameter expansion substring syntax to get the last character of a variable; no need for that awk bit in your var2:
#!/usr/bin/env bash
readarray -t lines < <(printf "%s\n" "Projekt/AX/include/ax.h" "Projekt/AX/src/ax.cpp")
for line in "${lines[#]}"; do
printf "%s\n%s\n" "$line" "${line: -1}" # Note the space before the -1
done
will display
Projekt/AX/include/ax.h
h
Projekt/AX/src/ax.cpp
p
I have a file test.txt like below spaces in between each record
service[1.1],parttion, service[1.2],parttion, service[1.3],parttion, service[2.1],parttion, service2[2.2],parttion,
Now I want to rearrange it as below into a output.txt
COMPOSITES=parttion/service/1.1,parttion/service/1.2,parttion/service/1.3,parttion/service/2.1,parttion/service/2.2
I've tried:
final_str=''
COMPOSITES=''
# Re-arranging the composites and preparing the composite property file
while read line; do
partition_val="$(echo $line | cut -d ',' -f 2)"
composite_temp1_val="$(echo $line | cut -d ',' -f 1)"
composite_val="$(echo $composite_temp1_val | cut -d '[' -f 1)"
version_temp1_val="$(echo $composite_temp1_val | cut -d '[' -f 2)"
version_val="$(echo $version_temp1_val | cut -d ']' -f 1)"
final_str="$partition_val/$composite_val/$version_val,"
COMPOSITES=$COMPOSITES$final_str
done <./temp/test.txt
We start with the file:
$ cat test.txt
service[1.1],parttion, service[1.2],parttion, service[1.3],parttion, service[2.1],parttion, service2[2.2],parttion,
We can rearrange that file as follows:
$ awk -F, -v RS=" " 'BEGIN{printf "COMPOSITES=";} {gsub(/[[]/, "/"); gsub(/[]]/, ""); if (NF>1) printf "%s%s/%s",NR==1?"":",",$2,$1;}' test.txt
COMPOSITES=parttion/service/1.1,parttion/service/1.2,parttion/service/1.3,parttion/service/2.1,parttion/service2/2.2
The same command split over multiple lines is:
awk -F, -v RS=" " '
BEGIN{
printf "COMPOSITES=";
}
{
gsub(/[[]/, "/")
gsub(/[]]/, "")
if (NF>1) printf "%s%s/%s",NR==1?"":",",$2,$1
}
' test.txt
Here's what I came up with.
awk -F '[],[]' -v RS=" " 'BEGIN{printf("COMPOSITES=")}/../{printf("%s/%s/%s,",$4,$1,$2);}' test.txt
Broken out for easier reading:
awk -F '[],[]' -v RS=" " '
BEGIN {
printf("COMPOSITES=");
}
/../ {
printf("%s/%s/%s,",$4,$1,$2);
}' test.txt
More detailed explanation of the script:
-F '[],[]' - use commas or square brackets as field separators
-v RS=" " - use just the space as a record separator
'BEGIN{printf("COMPOSITES=")} - starts your line
/../ - run the following code on any line that has at least two characters. This avoids the empty field at the end of a line terminating with a space.
printf("%s/%s/%s,",$4,$1,$2); - print the elements using a printf() format string that matches the output you specified.
As concise as this is, the format string does leave a trailing comma at the end of the line. If this is a problem, it can be avoided with a bit of extra code.
You could also do this in sed, if you like writing code in line noise.
sed -e 's:\([^[]*\).\([^]]*\).,\([^,]*\), :\3/\1/\2,:g;s/^/COMPOSITES=/;s/,$//' test.txt
Finally, if you want to avoid external tools like sed and awk, you can do this in bash alone:
a=($(<test.txt))
echo -n "COMPOSITES="
for i in "${a[#]}"; do
i="${i%,}"
t="${i%]*}"
printf "%s/%s/%s," "${i#*,}" "${i%[*}" "${t#*[}"
done
echo ""
This slurps the contents of test.txt into an array, which means your input data must be separated by whitespace, per your example. It then adds the prefix, then steps through the array, using Parameter Expansion to massage the data into the fields you need. The last line (echo "") is helpful for testing; you may want to eliminate it in practice.
This might be a very basic question but I was not able to find solution. I have a script:
If I run w | awk '{print $1}' in command line in my server I get:
f931
smk591
sc271
bx972
gaw844
mbihk988
laid640
smk59
ycc951
Now I need to use this list in my bash script one by one and manipulate some operation on them. I need to check their group and print those are in specific group. The command to check their group is id username. How can I save them or iterate through them one by one in a loop.
what I have so far is
tmp=$(w | awk '{print $1})
But it only return first record! Appreciate any help.
Populate an array with the output of the command:
$ tmp=( $(printf "a\nb\nc\n") )
$ echo "${tmp[0]}"
a
$ echo "${tmp[1]}"
b
$ echo "${tmp[2]}"
c
Replace the printf with your command (i.e. tmp=( $(w | awk '{print $1}') )) and man bash for how to work with bash arrays.
For a lengthier, more robust and complete example:
$ cat ./tstarrays.sh
# saving multi-line awk output in a bash array, one element per line
# See http://www.thegeekstuff.com/2010/06/bash-array-tutorial/ for
# more operations you can perform on an array and its elements.
oSET="$-"; set -f # save original set flags and turn off globbing
oIFS="$IFS"; IFS=$'\n' # save original IFS and make IFS a newline
array=( $(
awk 'BEGIN{
print "the quick brown"
print " fox jumped\tover\tthe"
print "lazy dogs back "
}'
) )
IFS="$oIFS" # restore original IFS value
set +f -$oSET # restore original set flags
for (( i=0; i < ${#array[#]}; i++ ));
do
printf "array[%d] of length=%d: \"%s\"\n" "$i" "${#array[$i]}" "${array[$i]}"
done
printf -- "----------\n"
printf -- "array[#]=\n\"%s\"\n" "${array[#]}"
printf -- "----------\n"
printf -- "array[*]=\n\"%s\"\n" "${array[*]}"
.
$ ./tstarrays.sh
array[0] of length=22: "the quick brown"
array[1] of length=23: " fox jumped over the"
array[2] of length=21: "lazy dogs back "
----------
array[#]=
"the quick brown"
array[#]=
" fox jumped over the"
array[#]=
"lazy dogs back "
----------
array[*]=
"the quick brown fox jumped over the lazy dogs back "
A couple of non-obvious key points to make sure your array gets populated with exactly what your command outputs:
If your command output can contain globbing characters than you should disable globbing before the command (oSET="$-"; set -f) and re-enable it afterwards (set +f -$oSET).
If your command output can contain spaces then set IFS to a newline before the command (oIFS="$IFS"; IFS=$'\n') and set it back to it's old value after the command (IFS="$oIFS").
tmp=$(w | awk '{print $1}')
while read i
do
echo "$i"
done <<< "$tmp"
You can use a for loop, i.e.
for user in $(w | awk '{print $1}'); do echo $user; done
which in a script would look nicer as:
for user in $(w | awk '{print $1}')
do
echo $user
done
You can use the xargs command to do this:
w | awk '{print $1}' | xargs -I '{}' id '{}'
With the -I switch, xargs will take each line of its standard input separately, then construct and execute a command line by replacing the specified string '{}' in the command line template with the input line
I guess you should use who instead of w. Try this out,
who | awk '{print $1}' | xargs -n 1 id
I'm developing a little script using ash shell (not bash).
Now i have a variable with the following composition:
VARIABLE = "number string status"
where number could be any number (actually between 1 and 18 but in the future that number could be higher) the string is a name and status is or on or off
The name usually is only lowercase letter.
Now my problem is to read only the string content in the variable, removing the number and the status.
How i can obtain that?
Two ways; one is to leverage $IFS and use a while loop - this will work for a single line quite happily - as:
echo "Part1 Part2 Part3" | while read a b c
do
echo $a
done
alternatively, use cut as follows:
a=`echo $var | cut -d' ' -f2`
echo $a
How about using cut?
name=$(echo "$variable" | cut -d " " -f 2)
UPDATE
Apparently, Ash doesn't understand $(...). Hopefully you can do this instead:
name=`echo "$variable" | cut -d " " -f 2`
How about :
name=$(echo "$variable" | awk '{print $2}')
#!/bin/sh
myvar="word1 word2 word3 wordX"
set -- $myvar
echo ${15} # outputs word 15