While loop in bash script execute only once [duplicate]

Question

I have a given shell script:

#!/bin/bash

USERNAME=xenobot
SSH_KEY_LOCATION="~/.ssh/id_rsa"
FILE="server.info"
while read -r server_ip  package_type; do  
    if [[ $package_type == "deb" ]]; then
         echo "For $server_ip package type is $package_type"
         DPKG_FILE_PATH=$(ls ./src/dpkg/dpkg-*)
             DPKG_FILE=$(basename $DPKG_FILE_PATH)
             echo "$DPKG_FILE located at $DPKG_FILE_PATH will be transfered via SSH to server"
         scp ./src/dpkg/${DPKG_FILE} $USERNAME@$server_ip:/tmp
             ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -l ${USERNAME} ${server_ip} "cd /tmp; sudo dpkg -i *.deb"
    elif [[ $package_type == "rpm" ]]; then
         echo "For $server_ip package type is $package_type"
             RPM_FILE_PATH=$(ls ./src/rpm/rpm-*)
             RPM_FILE=$(basename $RPM_FILE_PATH)
             echo "$RPM_FILE located at $RPM_FILE_PATH will be transfered via SSH to server"
         scp -o 'StrictHostKeyChecking no' ./src/rpm/${RPM_FILE} $USERNAME@$server_ip:/tmp
         echo "$RPM_FILE has been successfuly transfered to server!"
         ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -l ${USERNAME} ${server_ip} "cd /tmp; sudo rpm -ivh --force $RPM_FILE"
    fi
done <"$FILE"

And I have following file server.info, from which previous shell script reads:

213.136.80.123 rpm 213.136.91.102 rpm

The problem with it, as it is execute only once from first line, and just stops there without executing the second line

I have tried just to print output from this server.info using the same while read -r and it seems that outputs just fine like this

#!/bin/bash

USERNAME=xenobot
SSH_KEY_LOCATION="~/.ssh/id_rsa"
FILE="server.info"
while read -r server_ip  package_type; do  
    if [[ $package_type == "deb" ]]; then
         echo "For $server_ip package type is $package_type"
    elif [[ $package_type == "rpm" ]]; then
         echo "For $server_ip package type is $package_type"
    fi
done <"$FILE"

Output:

213.136.80.123 rpm 213.136.91.102 rpm

So it seems like it outputs two separate lines, however I do not know why it runs script only once in bigger example

No reason to use ls. Just rpm_file_path=(./src/rpm/rpm-*) to make rpm_file_path be an array. — Charles Duffy
– Charles Duffy, Commented Nov 21, 2022 at 21:40
(btw, suggesting rpm_file_path instead of RPM_FILE_PATH is deliberate: all-caps names are used for variables meaningful to the OS and shell; lowercase names are reserved for application use; see pubs.opengroup.org/onlinepubs/9699919799/basedefs/…, keeping in mind that setting a regular shell variable overwrites any like-named environment variable) — Charles Duffy
– Charles Duffy, Commented Nov 21, 2022 at 21:44
Also, the quotes in SSH_KEY_LOCATION="~/.ssh/id_rsa" are wrong; putting the ~ inside the quotes stops it from being expanded. Use ssh_key_location=~/.ssh/id_rsa, or ssh_key_location=~/".ssh/id_rsa" -- but don't quote the tilde if you want it replaced with the path to your home directory. If you want something that can be used in quotes, use $HOME (all caps because it's meaningful to POSIX-defined tools!) instead of ~. — Charles Duffy
– Charles Duffy, Commented Nov 21, 2022 at 21:46

amphetamachine · Accepted Answer · 2022-11-21 21:47:41Z

1

Try using a different file descriptor for your list other than 0, 1, or 2 (in this case it's set to 3).

while read -r server_ip package_type <&3; do
    ...
done 3<"$FILE"

If that works, then what's going on here is that ssh -- being an interactive program -- is sucking up your STDIN input.

answered Nov 21, 2022 at 21:47

amphetamachine

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1 Comment

Charles Duffy Over a year ago

In How to Answer, note the section Answer Well-Asked Questions, and the bullet point therein about questions that "have been asked and answered many times before".

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