I want to ask if is possible to combine linux command and <
sendmail -S "lalalal" -f "dailaakak" -au "kakakak" <<EOF
>lalal:lalal
>opp:ttt
>ggg:zzz
EOF
I want to have something like that sendmail -S "lalalal" -f "dailaakak" -au "kakakak" <<EOF; lalal:lalal; opp:ttt; ggg:zzz; EOF
I need to use that not in bash script
If it has to be in one line without newlines use that:
echo -e "lalal:lalal\nopp:ttt\nggg:zzz" | sendmail -S "lalalal" -f "dailaakak" -au "kakakak"
echo -n interpretes escapes characters such as \n as a newline.
If you are asking whether you can use the << EOF in an interactive shell then the answer is yes, you can.
Note this functionality is called here document and that there can be any word instead of EOF. For example:
$ cat - << someword
> Here you
> can
> write text with as many
> newlines as you want.
> someword
Here you
can
write text with as many
newlines as you want.
(cat - prints whatever it receives on stdin)
For more information on here documents you can read for example this: http://tldp.org/LDP/abs/html/here-docs.html
I have tried and succeeded but it's messy. EOF simply does not like to accept substituted new lines for some reason so it needs to be put in another format. Now I'm sure this could be achieved with an expect script one one line but the below is what I have made and works.
echo "ssh localhost `printf "<< EOF\necho "Working!" >> /tmp/myfile \nEOF\n"`" > file.sh; chmod770 file.sh; ./file.sh
printf "<< EOF\necho Test! >> /tmp/myfile \nEOF\n" | xargs ssh localhost
Please ensure chmod file permissions are suitable for your own work case! Putting it into an environment variable instead of a file is also likely to work.
Related
I am trying to automate the building of a config file and most of what I need can do done via a straight echo 'text here' >> myfile.conf
What I am having trouble with is appending the output of a command to the last line in the file.
My last working command is echo 'masternodeprivatekey=' >> myfile.conf
My next command is ./wallet-cli masternode genkey &>> myfile.conf
I need to have the masternode key generated to be included on the same line as masternodeprivatekey= so that the line will end up as this -
masternodeprivatekey=abcd13def456ghi789
Can this be done?
I have seen ppl suggest adding /c to the end of the echo command or -n to the end of the line however these don't work, they just add those characters to the end and still post the output of ./wallet-cli masternode genkey &>> myfile.conf on the next line.
Is it possible to do what I want? I'm pretty sure I could echo the output to two different temp files and then combine them, but is there an easier way?
You can use echo with option -n , it do not output the trailing newline
echo -n 'masternodeprivatekey=' >> myfile.conf
In sed, you can adress the last line with $
echo 'masternodeprivatekey=' >> myfile.conf
sed -i -r "$ s/(.*)/\1$(($RANDOM%100000))/" myfile.con
Check, whether your sed has -i and -r parameters. This worked with GNU-sed.
Since I don't know ./wallet-cli, I used something else in $(...) instead, to perform a command which generates output. So for you, it might be
sed -i -r "$ s/(.*)/\1$(./wallet-cli masternode genkey)" myfile.con
Since you seem to know before, that you will add something after the equal sign, why don't you do:
echo "masternodeprivatekey=$(./wallet-cli masternode genkey)" >> myfile.con
As per Mark Plotnick's suggestion, the use of printf instead of echo works perfectly.
I have this bash script:
databases=`mysql -h$DBHOST -u$DBUSER -p$DBPASSWORD -e "SHOW DATABASES;" | tr -d "| " | grep -v Database`
and the issue is when the password has all the characters possible. how can i escape the $DBPASSWORD in this case? If I have a password with '!' and given the fact that command is inside backticks. I have no experience in bash scripts but I've tried with "$DBPASSWORD" and with '$DBPASSWORD' and it doesn't work. Thank you
LATER EDIT: link to script here, line 170 -> https://github.com/Ardakilic/backmeup/blob/master/backmeup.sh
First: The answer from #bishop is spot on: Don't pass passwords on the command line.
Second: Use double quotes for all shell expansions. All of them. Always.
databases=$(mysql -h"$DBHOST" -u"$DBUSER" -p"$DBPASSWORD" -e "SHOW DATABASES;" | tr -d "| " | grep -v Database)
Don't pass the MySQL password on the command line. One, it can be tricky with passwords containing shell meta-characters (as you've discovered). Two, importantly, someone using ps can sniff the password.
Instead, either put the password into the system my.cnf, your user configuration file (eg .mylogin.cnf) or create an on-demand file to hold the password:
function mysql() {
local tmpfile=$(mktemp)
cat > "$tmpfile" <<EOCNF
[client]
password=$DBPASSWORD
EOCNF
mysql --defaults-extra-file="$tmpfile" -u"$DBUSER" -h"$DBHOST" "$#"
rm "$tmpfile"
}
Then you can run it as:
mysql -e "SHOW DATABASES" | tr -d "| " ....
mysql -e "SELECT * FROM table" | grep -v ...
See the MySQL docs on configuration files for further examples.
I sometimes have the same problem when automating activities:
I have a variable containing a string (usually a password) that is set in a config file or passed on the command-line, and that string includes the '!' character.
I need to pass that variable's value to another program, as a command-line argument.
If I pass the variable unquoted, or in double-quotes ("$password"), the shell tries to interpret the '!', which fails.
If I pass the variable in single quotes ('$password'), the variable isn't expanded.
One solution is to construct the full command in a variable and then use eval, for example:
#!/bin/bash
username=myuser
password='my_pass!'
cmd="/usr/bin/someprog -user '$username' -pass '$password'"
eval "$cmd"
Another solution is to write the command to a temporary file and then source the file:
#!/bin/bash
username=myuser
password='my_pass!'
cmd_tmp=$HOME/.tmp.$$
touch $cmd_tmp
chmod 600 $cmd_tmp
cat > $cmd_tmp <<END
/usr/bin/someprog -user '$username' -pass '$password'
END
source $cmd_tmp
rm -f $cmd_tmp
Using eval is simple, but writing a file allows for multiple complex commands.
P.S. Yes, I know that passing passwords on the command-line isn't secure - there is no need for more virtue-signalling comments on that topic.
I want to save a command to a file (for example I want to save the string "cat /etc/passwd" to a file) but I can't use the echo command.
How can I create and save string to a file directly without using echo command?
You can redirect cat to a file, type the text, and press Control-D when you're done, like this:
cat > file.txt
some text
some more text
^D
By ^D I mean to press Control-D at the end. The line must be empty.
It will not be part of the file, it is just to terminate the input.
Are you avoiding ECHO for security purposes (e.g. you're using a shared terminal and you don't want to leave trace in the shell history of what you've written inside your files) or you're just curious for an alternative method?
Simple alternative to echo:
As someone said, redirecting cat is probably the simpler way to go.
I'd suggest you to manually type your end-of-file, like this:
cat <<EOF > outputfile
> type here
> your
> text
> and finish it with
> EOF
Here's the string you're asking for, as an example:
cat <<EOF > myscript.sh
cat /etc/passwd
EOF
You probably don't want everyone to know you've peeked into that file, but if that's your purpose please notice that wrapping it inside an executable file won't make it more private, as that lines will be logged anyway...
Security - Avoiding history logs etc..
In modern shell, just try adding a space at the beginning of every command and use freely whatever you want.
BTW, my best hint is to avoid using that terminal at all, if you can. If you got two shells (another machine or even just another secure user in the same machine), I'd recommend you using netcat. See here: http://www.thegeekstuff.com/2012/04/nc-command-examples/?utm_source=feedburner
{ { command ls $(dirname $(which cat)) |
grep ^ca't$'; ls /etc/passwd; } |
tr \\n ' '; printf '\n'; } > output-file
But it's probably a lot simpler to just do : printf 'cat /etc/passwd\n'
To be clear, this is a tongue-in-cheek solution. The initial command is an extraordinarily convoluted way to get what you want, and this is intended to be a humorous answer. Perhaps instructive to understand.
I am not sure I understood you correctly but
cat /etc/passwd > target.file
use the > operator to write it to file without echoing
If you need to use it, inside a program :
cat <<EOF >file.txt
some text
some more text
EOF
I would imagine that you are probably trying to print the content of a string to a file, hence you mentioned echo.
You are avoiding this:
echo "cat /etc/passwd" > target.file
You can use a here string combined with cat.
cat > target.file <<< "cat /etc/passwd"
Now the file target.file will contain a string cat /etc/passwd.
$ cat target.file
cat /etc/passwd
$
To create string:
var1=your command
to save a file or variable in a file without echo use:
cat $FILE/VAR1 > /new/file/path
I have this part of script, which I cannot get to work. Been searching everywhere, but I must be missing something here.
export RULE=`cat iptables_sorted.txt`
ssh hostname << EOF
for line in $RULE; do
echo \$line >> test.txt (I have tried with and without slashes, etc...)
done
exit
EOF
After running this part of script, I get
stdin: is not a tty
-bash: line 2: syntax error near unexpected token `103.28.148.0/24'
-bash: line 2: `103.28.148.0/24'
...which is totally weird, because the iptables_sorted.txt is just full of ip ranges (when I run it locally, it works).
Newlines in $RULE cause the problem. Replace them by spaces:
RULE=$(< iptables_sorted.txt)
RULE=${RULE//$'\n'/ }
ssh hostname << EOF
for line in $RULE ; do
echo \$line >> test.txt
done
EOF
Note that this wouldn't work with lines containing whitespace.
Don't use for to iterate over a file; use while. This also demonstrates piping the output of the loop, not just every individual echo, to the remote host. cat is used to read the incoming data and redirect it to the final output file.
while IFS= read -r line; do
echo "$line"
done | ssh hostname 'cat > test.txt'
My code is given below. Echo works fine. But, the moment I redirect output of echo to touch, I get an error "no such file or directory". Why ? How do i fix it ?
If I copy paste the output of only echo, then the file is created, but not with touch.
while read line
do
#touch < echo -e "$correctFilePathAndName"
echo -e "$correctFilePathAndName"
done < $file.txt
If you have file names in each line of your input file file.txt then you don't need to do any loop. You can just do:
touch $(<file.txt)
to create all the files in one single touch command.
You need to provide the file name as argument and not via standard input. You can use command substitution via $(…) or `…`:
while read line
do
touch "$(echo -e "$correctFilePathAndName")"
done < $file.txt
Ehm, lose the echo part... and use the correct variable name.
while read line; do
touch "$line"
done < $file.txt
try :
echo -e "$correctFilePathAndName" | touch
EDIT : Sorry correct piping is :
echo -e "$correctFilePathAndName" | xargs touch
The '<' redirects via stdin whereas touch needs the filename as an argument. xargs transforms stdin in an argument for touch.