Tukukkk

So, I'm aware of that this topic has been discussed in several ways, but the responses didn't work for me.

I'm using sed to remove a line from a script, but each time I execute the bash script, I receive an error message "No such file or directory". I'm able run the command from the remote host terminal. See the sed command below.

#!/bin/bash



declare server_list="/location/of/iplist.txt"

declare file="/location/of/file/to/modify"

declare regex='"/export JAVA_HOME=/jvm/home/directory/java/d"'

declare file_content="$(sudo grep -Fxq export 

JAVA_HOME=/java/home/directory/java "${file}" )



declare script="sudo sed -i -e ${regex} ${file}"



date

cat ${server_list} |  while read server

do

# connect to each server and execute the "sed -i" command

ssh -I /location/of/pub/key ${server} -o StrictHostKeyChecking=no



# read file content into condition statement

${file_content}

if [ $? -eq 0 ];

then

    # confirm string exist and remove the line

    echo "JAVA_HOME located on ${server}"

    "${script}"

else

    echo "No JAVA_HOME located on ${server}"

fi

done

Don't put complete commands in variables. "${script}" is an invitation for trouble.

An illustrative example:

me ~ > echo -e 'foo barnbaz qux' > /tmp/foobar



me ~ > cat /tmp/foobar

foo bar

baz qux



me ~ > sed -e '/foo bar/d' /tmp/foobar

baz qux



me ~ > cmd="sed -e '/foo bar/d' /tmp/foobar"



me ~ > $cmd

sed: -e expression #1, char 1: unknown command: `''



me ~ > ${cmd}

sed: -e expression #1, char 1: unknown command: `''



me ~ > "$cmd"

bash: sed -e '/foo bar/d' /tmp/foobar: No such file or directory



me ~ > "${cmd}"

bash: sed -e '/foo bar/d' /tmp/foobar: No such file or directory

What's going on here? If you use $cmd unquoted, sed has following 4 arguments:

• -e


• '/foo


• bar/d'


• /tmp/foobar

(yes that's how "words" in bash work). Obviously sed cannot interpret this gibberish.

If you try running "$cmd" or "${cmd}", the entire string is interpreted as the command name, spaces quotes and all. The shell complains it cannot find an executable file named sed -e '/foo bar/d' /tmp/foobar, and it's absolutely right. No good either.

Solution?

A quick and dirty hack is

me ~ > eval ${cmd}

baz qux

Works as expected! However, eval is dangerous and should not be used unless you are a certified shell guru. (Which you, I believe, still are not). A better option is to define a function.

cmd() {

    sed -e '/foo bar/d' /tmp/foobar

}



...



cmd

Try to use eval to execute variable content

declare file="/location/of/file/to/modify"

declare regex='"/export JAVA_HOME=/jvm/home/directory/java/d"'

declare script="sudo sed -i -e ${regex} ${file}"

eval ${script}