Script is not loading the next line while reading

Question

My script is working but it's not reading the next line of the file .it is giving output for only one user not providing for next user from the users.txt file

#!/bin/bash

# Read the file containing the list of users to check
input_file="users.txt"

# Create empty files to hold the output
found_file="users_found.txt"
not_found_file="users_not_found.txt"
echo "" > $found_file
echo "" > $not_found_file

# Loop through each user in the input file
while read user; do
# Try to run the ldapsearch command for the user
if ssh -n ldaptest /opt/ldap/ldapsearch --user $user >/dev/null 2>&1; then
# User was found in LDAP, so append to the found file
echo "$user" >> $found_file
 else
  # User was not found in LDAP, so append to the not found file
 echo "$user" >> $not_found_file
 fi
 done < $input_file

The above script will check user is available in ldap or not.if user is available in ldap then it sends its output to found_file else it will send user to not_found_file here it's not reading input on second line.

cat -vet users.txt
Testuser1      $
Testuser1         $
Testuser3    $
Testuser4    $

Have a look at [this thread](https://stackoverflow.com/questions/10929453/read-a-file-line-by-line-assigning-the-value-to-a-variable/10929511#10929511) — fireshadow52, Apr 14 '23 at 02:39
There might be carriage returns on the file or [ssh is eating STDIN](https://mywiki.wooledge.org/BashFAQ/089) ... — Jetchisel, Apr 14 '23 at 02:46
I have tried with while read -r but still I'm getting same output — Randu, Apr 14 '23 at 03:16
Asking the obvious question: what does `users.txt` look like? Please add the output of `cat -vet users.txt` to your question. — tink, Apr 14 '23 at 21:18

score 0 · Accepted Answer · answered Apr 14 '23 at 05:43

0

This is a common issue while using for loop or while loop with ssh. After an execution ssh breaks the loop. Use below logic to get rid of this issue.

cat users.txt | while read user; do
   <Your ssh command>
done

answered Apr 14 '23 at 05:43

S. Mondal

54
5

_After an execution ssh breaks the loop_ .... Why? – user1934428 Apr 14 '23 at 06:09
1

The problem is that ssh reads from standard input, therefore it eats all your remaining lines. – S. Mondal Apr 14 '23 at 06:19
Isn't this only if I'm using `-T` (Disable pseudo-terminal allocation) or `-W` (port forwarding)? – user1934428 Apr 14 '23 at 09:42
It's not working I'm getting same output – Randu Apr 14 '23 at 09:51
Do not use -n with your ssh command, its prevent ssh to reading from stdin. – S. Mondal Apr 15 '23 at 02:31
I have tried without -n as well I'm getting same output. – Randu Apr 15 '23 at 04:44
Can you provide your new code here ? – S. Mondal Apr 16 '23 at 05:37
found_file="users_found.txt" not_found_file="users_not_found.txt" echo "" > $found_file echo "" > $not_found_file cat users.txt | while read user; do if ssh ldaptest /opt/ldap/ldapsearch --user $user >/dev/null 2>&1; then echo "$user" >> $found_file else # User was not found in LDAP, so append to the not found file echo "$user" >> $not_found_file fi done – Randu Apr 16 '23 at 10:27
found_file="users_found.txt" not_found_file="users_not_found.txt" echo "" > $found_file echo "" > $not_found_file cat users.txt | while read user; do ssh ldaptest /opt/ldap/ldapsearch --user $user >/dev/null 2>&1 if [ $? == 0 ]; then echo "$user" >> $found_file else # User was not found in LDAP, so append to the not found file echo "$user" >> $not_found_file fi done – S. Mondal Apr 16 '23 at 15:40
That worked I have added in script thankyou – Randu Apr 16 '23 at 18:04
Glad to here that, you are welcome. – S. Mondal Apr 17 '23 at 04:15

Script is not loading the next line while reading

1 Answers1