Initializing multiple variables in bash

Question

I have a file with this content:

$ cat init
Sample text
PM1:alex:1.2.3.4:22:passwordPM
PM2:alice:5.6.7.8:1212:Password
PM3:bob:9.10.11.12:1313:p@ssword
Some other text

Now I want to grep PM1 to PM3 and I want to set some variables and use them in my script:

user1="alex"
ip1="1.2.3.4"
port1="22"
pass1="password"
...

I need an structure could be used in more than PM1 to PM3. may be I have also PM10.

It's clear that we can grep each field but I don't know how we can use them.

grep PM init | cut -d: -f2
grep PM init | cut -d: -f3
grep PM init | cut -d: -f4
# I need to grep field number 5 in this way:
grep PM init | cut -d: -f5-

Update

I need to grep PM if the third letter is number. because if I don't do it may mixed up with passwords(last field).

It is much easier to do this in `awk` since data in row & column based using a common delimiter — anubhava, Jun 30 '20 at 06:12
`user1` is always `user1` it does not increment the number on it? — Jetchisel, Jun 30 '20 at 06:24
@Jetchisel user{number} ip{number} port{number} pass{number}, all should inherits PM{number} — M.J, Jun 30 '20 at 06:26
Does this answer your question? [How do I set a variable to the output of a command in Bash?](https://stackoverflow.com/questions/4651437/how-do-i-set-a-variable-to-the-output-of-a-command-in-bash) — kvantour, Jun 30 '20 at 06:58

Jetchisel · Accepted Answer · 2020-07-12T03:50:28.373

2

A slow if not the slowest bash shell solution for large data/size files.

#!/usr/bin/env bash

while read -r lines; do
  if [[ $lines == PM[0-9]* ]]; then
    IFS=: read -r pm user ip port pass <<< "$lines"
    n=${pm#*??}
    printf -v output 'user%s="%s"\nip%s="%s"\nport%s="%s"\npass%s="%s"' "$n" "$user" "$n" "$ip" "$n" "$port" "$n" "$pass"
    array+=("$output")
  fi
done < init

printf '%s\n' "${array[@]}"

The array can be separated in one line per entry, since the current solution groups the assignment and values per PM[0-9]*, if you loop over the array it should show what I'm talking about.

for i in "${array@]}"; do
  echo "$i"
  echo
done

Here is the separate entry for the array value and assignments, which can replace the current array structure depending on what you're doing.

printf -v user 'user%s="%s"' "$n" "$user"
printf -v ip 'ip%s="%s"' "$n" "$ip"
printf -v port 'port%s="%s"' "$n" "$port"
printf -v pass 'pass%s="%s"' "$n" "$pass"
array+=("$user" "$ip" "$port" "$pass")

edited Jul 12 '20 at 03:50

answered Jun 30 '20 at 06:29

Jetchisel

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That's great. How can we use and define these variables in a bash script? – M.J Jun 30 '20 at 06:39
Sorry it is a bash script now, I don't follow what you mean. – Jetchisel Jun 30 '20 at 06:43
just imagin I want to make ssh connection in this script so `printf` is not working I should define all of them as variables – M.J Jun 30 '20 at 06:44
using something like `eval` instead of `printf` should do the job, but how? – M.J Jun 30 '20 at 06:48
I have added an array, which should hold/contain the vairables and assignment. – Jetchisel Jun 30 '20 at 06:52
When running we have: unexpected EOF while looking for matching `"' – M.J Jun 30 '20 at 06:53
Sorry fixed, the missing `}` and now we are told to avoid extended conversation here. – Jetchisel Jun 30 '20 at 06:56

score 1 · Answer 2 · answered Jun 30 '20 at 13:08

A single sed command would do it (using GNU sed, inputfile is to be replaced with the actual input file name):

sed -E -n 's/^PM([0-9]+):([^:]*):([^:]*):([^:]*):(.*)/user\1="\2"\nip\1="\3"\nport\1="\4"\npass\1="\5"/p' inputfile

outputs

user1="alex"
ip1="1.2.3.4"
port1="22"
pass1="passwordPM"
user2="alice"
ip2="5.6.7.8"
port2="1212"
pass2="Password"
user3="bob"
ip3="9.10.11.12"
port3="1313"
pass3="p@ssword"

You can embed these generated variables in your script like that:

#!/bin/bash

# Generate name=value pairs from inputfile and save them in a temporary file /tmp/variables
sed -E -n 's/^PM([0-9]+):([^:]*):([^:]*):([^:]*):(.*)/user\1="\2"\nip\1="\3"\nport\1="\4"\npass\1="\5"/p' inputfile > /tmp/variables || exit

# "Source" the file into script 
. /tmp/variables
# Temporary file is not needed any longer. You can remove it if you want

# You can use generated variable names from now on:
echo "user1=$user1"
# and the like

Initializing multiple variables in bash

2 Answers2