I'm having difficulty getting the correct variable substitution to work within this function, especially the use of echo "$(...) string.
outputOFF ()
{
host='mydevreporting.com'
_pw='123456foobar'
_dt=$(date +'%m-%d-%y')
exp="SELECT * FROM metrics.account_use where account='foo' and profile='bar' order by date desc;";
echo "$(grep real < <({ time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"} 2>&1)):localhost:${_dt}"
#echo "$(grep real < <(\{ time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"\} 2>&1)):localhost:${_dt}"
}
From the command line, it will work:
echo "$(grep real < <({ time mysql -u admin -p123456foobar -h mydevreporting.com -N -e "SELECT * FROM metrics.account_use where account='foo' and profile='bar' order by date desc;"; } 2>&1)):localhost:$(date +'%m-%d-%y')"
As I'm seeing error messages:
./tst.sh: command substitution: line 40: syntax error near unexpected token `)'
./tst.sh: command substitution: line 40: `{ time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"} 2>&1)'
As you can see the echo "$(...) is inside this function outputOFF().
I've also tried escaping the braces \{, \}, which allows the variables to substitute, but somehow that command isn't working as it should.
echo "$(grep real < <(\{ time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"\} 2>&1)):localhost:${_dt}"
So, i'm stuck.
You are missing a ; in the {...} group expression, after "$exp" (see this documentation for why). Here is the corrected version:
echo "$(grep real < <({ time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"; } 2>&1)):localhost:${_dt}"
Less braces makes it more readable, at least for me.
result=$( { time mysql -u admin -p${_pw} -h ${host} -N -e "$exp"; } 2>&1 | grep real );
echo "${result}:localhost:${_dt}"
time is reporting on stderr. Thus the {} are neceessary to capture the output.
Or discarding the result, and only capture the result of time.
result=$( { time mysql -u admin -p${_pw} -h ${host} -N -e "$exp" >/dev/null; } 2>&1 )
echo ${result}":localhost:${_dt}"
The unquoted ${result} is printed without the newlines. Thus you can keep all information from time with the additional timestamp.
Related
I am fetching the data from psql in the shell script and assign to the global variable but the global variable is not updating below i have tried:
#!/bin/bash
res_count=0
psql -h $db_host -U $db_user -d $db_name -At -c "select count(id) as dCount from abc" --no-password --field-separator ' ' | \
while read dCount ; do
res_count=$dCount
done;
echo $res_count
$res_count is not updating, it has still value 0, please correct me where i am wrong thanks
Your while loop executes in a subshell because it is executed as part of the pipeline. You can avoid it by using lastpipe or placing the psql command inside process substitution.
#/bin/bash
shopt -s lastpipe
...
Or
res_count=0
while read dCount ; do
res_count=$dCount
done < <(psql -h "$db_host" -U "$db_user" -d "$db_name" -At \
-c "select count(id) as dCount from abc"
--no-password --field-separator ' ')
echo "$res_count"
As a side note, quote your variables properly.
I'm trying to make the private key SSH connection with LDAP.
/etc/ssh/sshd_config
AuthorizedKeysCommand /etc/ldap_ssh_authorized_keys.sh
AuthorizedKeysCommandUser nobody
Script to get public keys from LDAP server
/etc/ldap_ssh_authorized_keys.sh
#!/bin/bash
USERSLIST=$( ldapsearch -x -D "${LDAP_USER}" -w "${LDAP_PASSWORD}" -H $LDAP_URI -b "${LDAP_BASEDN}" -s sub '(objectClass=posixAccount)' -u 'uid' \
grep '^uid:' | sed -n '/^ /{H;d};/uid:/x;$g;s/\n *//g;s/uid: //gp' \
)
while IFS= read -r line; do
exists=$(ldapsearch -x -D "${LDAP_USER}" -w "${LDAP_PASSWORD}" -H $LDAP_URI -b "${LDAP_BASEDN}" \
-s sub "(&(objectClass=posixGroup)(cn=sysadmin)(memberUid=${line}))" | grep "^# numEntries:")
if [[ ! -z $exists ]]
then
ldapsearch -x -D "${LDAP_USER}" -w "${LDAP_PASSWORD}" -H $LDAP_URI -b "${LDAP_BASEDN}" \
-s sub "(&(objectClass=posixAccount)(uid=${line}))" \
-u 'sshPublicKey' \
| sed -n '/^ /{H;d};/sshPublicKey:/x;$g;s/\n *//g;s/sshPublicKey: //gp'
echo -e "";
fi;
done <<< "$USERSLIST"
When I'm running script with /bin/bash it's working well and return my public keys.
All environment variables defined normally.
LDAP_URI
LDAP_BASEDN
LDAP_USER
LDAP_PASSWORD
The script also running normally when trying to make an SSH connection. But environment variables not available.
I'm trying also with AuthorizedKeysCommandUser as root. But nothing changed.
I solved this problem by getting the environment variables from /proc/1/environ.
Reference
I'm kind of new in bash script and postgresql.
I saw in another question a way to run a bash script as psql user here.
I tried making a bash function as follow,
postgres_create_db(){
sudo su postgres <<- EOF
if psql -lqt | cut -d \| -f 1 | grep -qw nokia_aaa_poc_db; then
psql -c '\dt'
else
psql -c 'CREATE DATABASE nokia_AAA_poc_db;'
fi
EOF
exit
}
where this function will be called further in code, but I wonder if I can add a RETURN to the function that's actualy returning a varible that was first declared inside postgres bash (in between the EOF's). Like bellow:
postgres_create_db(){
sudo su postgres <<- EOF
if psql -lqt | cut -d \| -f 1 | grep -qw nokia_aaa_poc_db; then
psql -c '\dt'
exists=1 #where thats a variable that I want to access outside the postgres bash.
else
psql -c 'CREATE DATABASE nokia_AAA_poc_db;'
fi
EOF
exit
return exists
}
but it gives an error on shellcheck
return exists
^-- SC2152: Can only return 0-255. Other data should be written to stdout.
Functions in bash can only return values from 0 to 255 where 0 is success. Reference: Return value in a Bash function
So you can echo the variable like this instead:
#!/usr/bin/env bash
postgres_test() {
psql -c '\dt' &> /dev/null
declare exists=1
echo $exists
}
printf "%s\n" "$(postgres_test)"
This prints "1".
You'll also notice that I redirected the output of the Postgres command to /dev/null. This is because it would be combined in the function's output otherwise.
You might wish to redirect that output to a file instead.
Trying it this way:
#!/bin/bash
myvals=`psql -d mydb -c "select id from table1 where 't'"`
ssh user1#host1.domain.tld "for i in $myvals; do echo \$i >> values; done"
As long as psql returns just one value, it works fine. But if its several values, I receive this response:
bash: -c: line 1: syntax error near unexpected token `2'
bash: -c: line 1: `2'
Also, I tried to:
myvals='1 2 3'
And then it works fine: the values 1 2 3 are appended to the "values" file on the remote host; no error mesages.
If I try another subshell command, such as myvals=ls /bin, errors reappear.
It's clear that $myvals is evaluated on the local host already but what makes the subshell results so different?
If It's Not Really An Array...
Iterating over a string as if it were an array is innately buggy. Don't do it. That said, to generate a safely-escaped (eval-safe) version of your value, use printf %q.
#!/bin/bash
myvals=`psql -d mydb -c "select id from table1 where 't'"`
printf -v myvals_q %q "$myvals"
ssh user1#host1.domain.tld \
"myvals=$myvals_q;"' for i in $myvals; do echo "$i"; done >>values'
If You Actually Had An Array
#!/bin/bash
readarray -t myvals < <(psql -d mydb -c "select id from table1 where 't'")
printf -v myvals_q '%q ' "${myvals[#]}"
ssh user1#host1.domain.tld \
"myvals=( $myvals_q );"' for i in "${myvals[#]}"; do echo "$i"; done >>values'
If You Don't Need To Store The Value Locally In The First Place
#!/bin/bash
ssh user1#host1.domain.tld \
'while read -r i; do echo "$i"; done >>values' \
< <(psql -d mydb -c "select id from table1 where 't'")
General Notes
Running echo "$i" >>values over and over in a loop is inefficient: Every time the line is run, it re-opens the values file. Instead, run the redirection >values over the whole loop; this truncates the file exactly once, at the loop's start, and appends all values generated therein.
Unquoted expansions are generally dangerous. For example, if foo='*', then $foo will be replaced with a list of files in the current directory, but "$foo" will emit the exact contents -- *. Similarly, tabs, whitespace runs, and various other contents can be unintentionally damaged by unquoted expansion, even when passing directly to echo.
You can switch quoting types in the same string -- thus, "$foo"'$foo' is one string, the first part of which is replaced with the value of the variable named foo, and the second component of which is the exact string $foo.
You can send the output as a file:
#!/bin/bash
psql -d mydb -c "select id from table1 where 't'" > /tmp/values
scp values user1#host1.domain.tld:/tmp/
or pipe it to the remote host:
psql -d mydb -c "select id from table1 where 't'" | \
ssh user1#host1.domain.tld 'while read line; do echo $line; done'
I've got a snippet here that i'm running on the command line which creates the following output:
$ { time mysql -u root -N -e "select NOW();" >/dev/null; } 2>&1 | grep real; echo ":localhost:"; date +"%m-%d-%y"
real 0m0.022s
:localhost:
04-28-17
I'd like my output to be a single string like so: (or delimited by whatever I choose as delimiter if possible)
real 0m0.022s :localhost:04-28-17
What command can I use to concat or join to create my string? Thanks.
Something like this should work, assuming bash as your shell:
echo "$(grep real < <({ time mysql -u root -N -e 'select NOW();'; } 2>&1)):localhost:$(date +'%m-%d-%y')"
The first $(...) could also be your original { time mysql -u root -N -e 'select NOW();'; } 2>&1 | grep real. I don't see a particularly compelling reason to prefer one way over the other.
The core concept, though, is that doing echo "$(...)" strips trailing newlines off the output of whatever's inside $(...)...
You can just wrap that whole beast up and send it to sed to wipe out the linefeeds:
{ { time mysql -u root -N -e "select NOW();" >/dev/null; } 2>&1 | grep real; echo ":localhost:"; date +"%m-%d-%y"; } | sed ':a;N;$!ba;s/\n/ /g'
In Action:
$ { { time mysql -u root -N -e "select NOW();" >/dev/null; } 2>&1 | grep real; echo ":localhost:"; date +"%m-%d-%y"; } | sed ':a;N;$!ba;s/\n/ /g'
real 0m0.412s :localhost: 04-28-17