Append a line to end of sshd.conf - bash

Trying to append an entry to the last line of sshd.conf however it appends it to the end of the previous line.
echo -e "DenyGroups $(echo ${admin_membership_ad_group} | cut -f2 -d= |cut -f1 -d,|awk '{print tolower($0)}')" >> /etc/ssh/sshd.conf
and
echo "\nDenyGroups $(echo ${admin_membership_ad_group} | cut -f2 -d= |cut -f1 -d,|awk '{print tolower($0)}')" >> /etc/ssh/sshd.conf
Expectation:
Lastline
DenyGroups somegroup
Result:
LastlineDenyGroups somegroup

With GNU sed:
sed -i '$a DenyGroups '"${admin_membership_ad_group}" /etc/ssh/sshd.conf
$: refers to the last line
a: append

In your last command you have forgotten the -e, see the test below:
$ # Create test file
$ echo -n LastLine > tst
$ # See what happens if you forget -e
$ echo -n '\n + echo without -e' >> tst
$ # Now add -e
$ echo -e "\nDenyGroups $(echo admin_membership_ad_group)" >> tst
$ # See the results
$ cat tst
LastLine\n + echo without -e
DenyGroups admin_membership_ad_group
Note that in the other shells builtin echo behaves differently. For instance in zsh the expansion of \n will happen even without specifying the -e option.

Related

How to remove first & last character in bash string

#!/bin/bash
MA=$(bt-device -l | cut -d " " -f 3)
MAC=${MA:1: -1}
bluetoothctl connect $MAC
Expected Result
98:9E:63:18:00:88
Actual result
(98:9E:63:18:00:88
A few alternatives:
$ echo 'Denny’s Tunez (98:9E:63:18:00:88)' | sed -En 's/^[^(]*\(([^)]*)\).*/\1/p'
98:9E:63:18:00:88
$ echo 'Denny’s Tunez (98:9E:63:18:00:88)' | cut -d'(' -f2 | cut -d')' -f1
98:9E:63:18:00:88
$ echo 'Denny’s Tunez (98:9E:63:18:00:88)' | awk -F'[)(]' '{print $2}'
98:9E:63:18:00:88
$ echo 'Denny’s Tunez (98:9E:63:18:00:88)' | grep -Eow '(..)(:..){5}'
98:9E:63:18:00:88
$ x='Denny’s Tunez (98:9E:63:18:00:88)'
$ y="${x//*\(/}"
$ y="${y//\)*}"
$ echo $y
98:9E:63:18:00:88
With GNU bash and its Parameter Expansion:
s="(98:9E:63:18:00:88)"
s="${s/#?/}" # remove first character
s="${s/%?/}" # remove last character
echo "$s"
Output:
98:9E:63:18:00:88
Using sed it can be done in a single step:
s='Denny’s Tunez (98:9E:63:18:00:88)'
echo "$s" | sed -E 's/.* \(|)//g'
98:9E:63:18:00:88
So for your example you can use:
mac=$(bt-device -l | sed -E 's/.* \(|)//g')
You can use parameter expansion:
offset and length
echo ${MA:1: -1}
prefix and suffix removal
tmp=${MA#(}
echo ${tmp%)}
parameter matching
tmp=${MA/#\(}
echo ${tmp/%\)}
Another approach is to:
whitelist what you do want
echo "$MA" | tr -dC '[0-9A-F:]'

How to trim a string in shell script

I have a string,
var=refs/heads/testing/branch
I want to get rid of refs/heads/ in the string using shell script, such that I have only:
var=testing/branch
Commands I tried (one per line):
echo $(var) | awk -F\\ {'print $2'}
echo $var | sed -e s,refs/heads/,,
echo "refs/heads/testing/branch" | grep -oP '(?<=refs/heads/\)\w+'
echo "refs/heads/testing/branch" | LC_ALL=C sed -e 's/.*\\//'
echo "refs/heads/testing/branch" | cut -d'\' -f2
echo refs/heads/testing/branch | sed -e s,refs/heads/,,
there are lots of options out there ,try easy ones:
echo $var | cut -d "/" -f 3,4
echo $var | awk -F"/" '{print $3"/"$4}'
Shell parameter expansion: remove the prefix "refs/heads/" from the variable contents
$ var=refs/heads/testing/branch
$ echo "${var#refs/heads/}"
testing/branch

replacement for cut --output-delimiter

I created a script that was using
cut -d',' -f- --output-delimiter=$'\n'
to add a newline for each command separated value in RHEL 5, for e.g.
[root]# var="hi,hello how,are you,doing"
[root]# echo $var
hi,hello how,are you,doing
[root]# echo $var|cut -d',' -f- --output-delimiter=$'\n'
hi
hello how
are you
doing
But unfortunately when I run the same command in Solaris 10, it doesn't work at all :( !
bash-3.00# var="hi,hello how,are you,doing"
bash-3.00# echo $var
hi,hello how,are you,doing
bash-3.00# echo $var|cut -d',' -f- --output-delimiter=$'\n'
cut: illegal option -- output-delimiter=
usage: cut -b list [-n] [filename ...]
cut -c list [filename ...]
cut -f list [-d delim] [-s] [filename]
I checked the man page for 'cut' and alas there is no ' --output-delimiter ' in there !
So how do I achieve this in Solaris 10 (bash)? I guess awk would be a solution, but I'm unable to frame up the options properly.
Note: The comma separated variables might have " " space in them.
What about using tr for this?
$ tr ',' '\n' <<< "$var"
hi
hello how
are you
doing
or
$ echo $var | tr ',' '\n'
hi
hello how
are you
doing
With sed:
$ sed 's/,/\n/g' <<< "$var"
hi
hello how
are you
doing
Or with awk:
$ awk '1' RS=, <<< "$var"
hi
hello how
are you
doing
Perhaps do it in bash itself?
var="hi,hello how,are you,doing"
printf "$var" | (IFS=, read -r -a arr; printf "%s\n" "${arr[#]}")
hi
hello how
are you
doing

" echo" in bash script empty file

I have problem with echo command I need export data to csv but its empty file
#!/bin/bash
while read domain
do
ownname= whois $domain | grep -A 1 -i "Administrative Contact:" |cut -d ":" -f 2 | sed 's/ //' | sed -e :a -e '$!N;s/ \n/,/;ta'
echo -e "$ownname" >> test.csv
done < dom.txt
You need to use command substitution to store command's output in a shell variable:
#!/bin/bash
while read domain; do
ownname=$(whois $domain | grep -A 1 -i "Administrative Contact:" |cut -d ":" -f 2 | sed 's/ //' | sed -e :a -e '$!N;s/ \n/,/;ta')
echo -e "$ownname" >> test.csv
done
PS: I haven't tested all the piped commands.

Redirect output to a bash array

I have a file containing the string
ipAddress=10.78.90.137;10.78.90.149
I'd like to place these two IP addresses in a bash array. To achieve that I tried the following:
n=$(grep -i ipaddress /opt/ipfile | cut -d'=' -f2 | tr ';' ' ')
This results in extracting the values alright but for some reason the size of the array is returned as 1 and I notice that both the values are identified as the first element in the array. That is
echo ${n[0]}
returns
10.78.90.137 10.78.90.149
How do I fix this?
Thanks for the help!
do you really need an array
bash
$ ipAddress="10.78.90.137;10.78.90.149"
$ IFS=";"
$ set -- $ipAddress
$ echo $1
10.78.90.137
$ echo $2
10.78.90.149
$ unset IFS
$ echo $# #this is "array"
if you want to put into array
$ a=( $# )
$ echo ${a[0]}
10.78.90.137
$ echo ${a[1]}
10.78.90.149
#OP, regarding your method: set your IFS to a space
$ IFS=" "
$ n=( $(grep -i ipaddress file | cut -d'=' -f2 | tr ';' ' ' | sed 's/"//g' ) )
$ echo ${n[1]}
10.78.90.149
$ echo ${n[0]}
10.78.90.137
$ unset IFS
Also, there is no need to use so many tools. you can just use awk, or simply the bash shell
#!/bin/bash
declare -a arr
while IFS="=" read -r caption addresses
do
case "$caption" in
ipAddress*)
addresses=${addresses//[\"]/}
arr=( ${arr[#]} ${addresses//;/ } )
esac
done < "file"
echo ${arr[#]}
output
$ more file
foo
bar
ipAddress="10.78.91.138;10.78.90.150;10.77.1.101"
foo1
ipAddress="10.78.90.137;10.78.90.149"
bar1
$./shell.sh
10.78.91.138 10.78.90.150 10.77.1.101 10.78.90.137 10.78.90.149
gawk
$ n=( $(gawk -F"=" '/ipAddress/{gsub(/\"/,"",$2);gsub(/;/," ",$2) ;printf $2" "}' file) )
$ echo ${n[#]}
10.78.91.138 10.78.90.150 10.77.1.101 10.78.90.137 10.78.90.149
This one works:
n=(`grep -i ipaddress filename | cut -d"=" -f2 | tr ';' ' '`)
EDIT: (improved, nestable version as per Dennis)
n=($(grep -i ipaddress filename | cut -d"=" -f2 | tr ';' ' '))
A variation on a theme:
$ line=$(grep -i ipaddress /opt/ipfile)
$ saveIFS="$IFS" # always save it and put it back to be safe
$ IFS="=;"
$ n=($line)
$ IFS="$saveIFS"
$ echo ${n[0]}
ipAddress
$ echo ${n[1]}
10.78.90.137
$ echo ${n[2]}
10.78.90.149
If the file has no other contents, you may not need the grep and you could read in the whole file.
$ saveIFS="$IFS"
$ IFS="=;"
$ n=$(</opt/ipfile)
$ IFS="$saveIFS"
A Perl solution:
n=($(perl -ne 's/ipAddress=(.*);/$1 / && print' filename))
which tests for and removes the unwanted characters in one operation.
You can do this by using IFS in bash.
First read the first line from file.
Seoncd convert that to an array with = as delimeter.
Third convert the value to an array with ; as delimeter.
Thats it !!!
#!/bin/bash
IFS='\n' read -r lstr < "a.txt"
IFS='=' read -r -a lstr_arr <<< $lstr
IFS=';' read -r -a ip_arr <<< ${lstr_arr[1]}
echo ${ip_arr[0]}
echo ${ip_arr[1]}

Resources