How do I represent a newline character in bash inline string shell replacement? - bash

I can modify a string like the following:
mod=${orig//[xyz]/_}
It will replace all occurances of [xyz] with _
But if I have a string such as eth0 eth1 eth2, how do I replace ' ' space with newline \n. The following does not work.
orig="eth0 eth1 eth2"
mod=${orig// /\n}
This is how I'm planning to use it:
VRRP_INTERFACE="${VRRP_INTERFACE:-ib0}"
VRRP_ADDITIONAL_INTERFACES="${VRRP_ADDITIONAL_INTERFACES// /\\n}"
cat << EOF > /etc/keepalived/keepalived.conf
vrrp_instance VI_1 {
interface ${VRRP_INTERFACE}
state BACKUP
virtual_router_id ${VRRP_ROUTER_ID}
priority ${VRRP_PRIORITY}
advert_int 1
# Monitor these as well
track_interface {
$VRRP_ADDITIONAL_INTERFACES
}
virtual_ipaddress {
${VRRP_VIP} dev ${VRRP_INTERFACE} label ${VRRP_INTERFACE}:1
}
EOF
I note that if I use
echo -e $VRRP_ADDITIONAL_INTERFACES it works when the string contains a "\n" in the string. i.e. replace with \n rather than \n.
But in the case of using cat << EOF > filename format it doesn't work.

Use $'\n':
$ orig="eth0 eth1 eth2"
$ mod=${orig// /$'\n'}
$ echo "$mod"
eth0
eth1
eth2
This approach puts actual newline characters into the string mod.
Using cat << EOF
Consider this shell script which uses the same substitution:
orig="eth0 eth1 eth2"
mod=${orig// /$'\n'}
cat << EOF > test.txt
track_interface {
$mod
}
EOF
cat test.txt
When run, this is the output:
$ bash script.sh
track_interface {
eth0
eth1
eth2
}
Note that this approach requires bash. Thus, on debian-like systems (for which sh is dash), the following will not work:
$ sh script.sh
matt.sh: 2: script.sh: Bad substitution

I figured out a method. It's not as pretty but works.
Assign the cat to a variable FILE.
Then echo -e "$FILE" > filename
i.e.
VRRP_INTERFACE="${VRRP_INTERFACE:-ib0}"
VRRP_ADDITIONAL_INTERFACES="${VRRP_ADDITIONAL_INTERFACES// /'\n'}"
FILE=$(cat << EOF
vrrp_instance VI_1 {
interface ${VRRP_INTERFACE}
state BACKUP
virtual_router_id ${VRRP_ROUTER_ID}
priority ${VRRP_PRIORITY}
advert_int 1
# Monitor these as well
track_interface {
$VRRP_ADDITIONAL_INTERFACES
}
virtual_ipaddress {
${VRRP_VIP} dev ${VRRP_INTERFACE} label ${VRRP_INTERFACE}:1
}
EOF
)
echo -e "$FILE" > /etc/keepalived/keepalived.conf

#John1024 solution, works well
orig="eth0 eth1 eth2"
mod=${orig// /$'\n'}
cat << EOF > test.txt
track_interface {
$mod
}
EOF

Related

How can extract a value from .ini using sed [duplicate]

I have a parameters.ini file, such as:
[parameters.ini]
database_user = user
database_version = 20110611142248
I want to read in and use the database version specified in the parameters.ini file from within a bash shell script so I can process it.
#!/bin/sh
# Need to get database version from parameters.ini file to use in script
php app/console doctrine:migrations:migrate $DATABASE_VERSION
How would I do this?
How about grepping for that line then using awk
version=$(awk -F "=" '/database_version/ {print $2}' parameters.ini)
You can use bash native parser to interpret ini values, by:
$ source <(grep = file.ini)
Sample file:
[section-a]
var1=value1
var2=value2
IPS=( "1.2.3.4" "1.2.3.5" )
To access variables, you simply printing them: echo $var1. You may also use arrays as shown above (echo ${IPS[#]}).
If you only want a single value just grep for it:
source <(grep var1 file.ini)
For the demo, check this recording at asciinema.
It is simple as you don't need for any external library to parse the data, but it comes with some disadvantages. For example:
If you have spaces between = (variable name and value), then you've to trim the spaces first, e.g.
$ source <(grep = file.ini | sed 's/ *= */=/g')
Or if you don't care about the spaces (including in the middle), use:
$ source <(grep = file.ini | tr -d ' ')
To support ; comments, replace them with #:
$ sed "s/;/#/g" foo.ini | source /dev/stdin
The sections aren't supported (e.g. if you've [section-name], then you've to filter it out as shown above, e.g. grep =), the same for other unexpected errors.
If you need to read specific value under specific section, use grep -A, sed, awk or ex).
E.g.
source <(grep = <(grep -A5 '\[section-b\]' file.ini))
Note: Where -A5 is the number of rows to read in the section. Replace source with cat to debug.
If you've got any parsing errors, ignore them by adding: 2>/dev/null
See also:
How to parse and convert ini file into bash array variables? at serverfault SE
Are there any tools for modifying INI style files from shell script
Sed one-liner, that takes sections into account. Example file:
[section1]
param1=123
param2=345
param3=678
[section2]
param1=abc
param2=def
param3=ghi
[section3]
param1=000
param2=111
param3=222
Say you want param2 from section2. Run the following:
sed -nr "/^\[section2\]/ { :l /^param2[ ]*=/ { s/[^=]*=[ ]*//; p; q;}; n; b l;}" ./file.ini
will give you
def
Bash does not provide a parser for these files. Obviously you can use an awk command or a couple of sed calls, but if you are bash-priest and don't want to use any other shell, then you can try the following obscure code:
#!/usr/bin/env bash
cfg_parser ()
{
ini="$(<$1)" # read the file
ini="${ini//[/\[}" # escape [
ini="${ini//]/\]}" # escape ]
IFS=$'\n' && ini=( ${ini} ) # convert to line-array
ini=( ${ini[*]//;*/} ) # remove comments with ;
ini=( ${ini[*]/\ =/=} ) # remove tabs before =
ini=( ${ini[*]/=\ /=} ) # remove tabs after =
ini=( ${ini[*]/\ =\ /=} ) # remove anything with a space around =
ini=( ${ini[*]/#\\[/\}$'\n'cfg.section.} ) # set section prefix
ini=( ${ini[*]/%\\]/ \(} ) # convert text2function (1)
ini=( ${ini[*]/=/=\( } ) # convert item to array
ini=( ${ini[*]/%/ \)} ) # close array parenthesis
ini=( ${ini[*]/%\\ \)/ \\} ) # the multiline trick
ini=( ${ini[*]/%\( \)/\(\) \{} ) # convert text2function (2)
ini=( ${ini[*]/%\} \)/\}} ) # remove extra parenthesis
ini[0]="" # remove first element
ini[${#ini[*]} + 1]='}' # add the last brace
eval "$(echo "${ini[*]}")" # eval the result
}
cfg_writer ()
{
IFS=' '$'\n'
fun="$(declare -F)"
fun="${fun//declare -f/}"
for f in $fun; do
[ "${f#cfg.section}" == "${f}" ] && continue
item="$(declare -f ${f})"
item="${item##*\{}"
item="${item%\}}"
item="${item//=*;/}"
vars="${item//=*/}"
eval $f
echo "[${f#cfg.section.}]"
for var in $vars; do
echo $var=\"${!var}\"
done
done
}
Usage:
# parse the config file called 'myfile.ini', with the following
# contents::
# [sec2]
# var2='something'
cfg.parser 'myfile.ini'
# enable section called 'sec2' (in the file [sec2]) for reading
cfg.section.sec2
# read the content of the variable called 'var2' (in the file
# var2=XXX). If your var2 is an array, then you can use
# ${var[index]}
echo "$var2"
Bash ini-parser can be found at The Old School DevOps blog site.
Just include your .ini file into bash body:
File example.ini:
DBNAME=test
DBUSER=scott
DBPASSWORD=tiger
File example.sh
#!/bin/bash
#Including .ini file
. example.ini
#Test
echo "${DBNAME} ${DBUSER} ${DBPASSWORD}"
All of the solutions I've seen so far also hit on commented out lines. This one didn't, if the comment code is ;:
awk -F '=' '{if (! ($0 ~ /^;/) && $0 ~ /database_version/) print $2}' file.ini
You may use crudini tool to get ini values, e.g.:
DATABASE_VERSION=$(crudini --get parameters.ini '' database_version)
one of more possible solutions
dbver=$(sed -n 's/.*database_version *= *\([^ ]*.*\)/\1/p' < parameters.ini)
echo $dbver
Display the value of my_key in an ini-style my_file:
sed -n -e 's/^\s*my_key\s*=\s*//p' my_file
-n -- do not print anything by default
-e -- execute the expression
s/PATTERN//p -- display anything following this pattern
In the pattern:
^ -- pattern begins at the beginning of the line
\s -- whitespace character
* -- zero or many (whitespace characters)
Example:
$ cat my_file
# Example INI file
something = foo
my_key = bar
not_my_key = baz
my_key_2 = bing
$ sed -n -e 's/^\s*my_key\s*=\s*//p' my_file
bar
So:
Find a pattern where the line begins with zero or many whitespace characters,
followed by the string my_key, followed by zero or many whitespace characters, an equal sign, then zero or many whitespace characters again. Display the rest of the content on that line following that pattern.
Similar to the other Python answers, you can do this using the -c flag to execute a sequence of Python statements given on the command line:
$ python3 -c "import configparser; c = configparser.ConfigParser(); c.read('parameters.ini'); print(c['parameters.ini']['database_version'])"
20110611142248
This has the advantage of requiring only the Python standard library and the advantage of not writing a separate script file.
Or use a here document for better readability, thusly:
#!/bin/bash
python << EOI
import configparser
c = configparser.ConfigParser()
c.read('params.txt')
print c['chassis']['serialNumber']
EOI
serialNumber=$(python << EOI
import configparser
c = configparser.ConfigParser()
c.read('params.txt')
print c['chassis']['serialNumber']
EOI
)
echo $serialNumber
sed
You can use sed to parse the ini configuration file, especially when you've section names like:
# last modified 1 April 2001 by John Doe
[owner]
name=John Doe
organization=Acme Widgets Inc.
[database]
# use IP address in case network name resolution is not working
server=192.0.2.62
port=143
file=payroll.dat
so you can use the following sed script to parse above data:
# Configuration bindings found outside any section are given to
# to the default section.
1 {
x
s/^/default/
x
}
# Lines starting with a #-character are comments.
/#/n
# Sections are unpacked and stored in the hold space.
/\[/ {
s/\[\(.*\)\]/\1/
x
b
}
# Bindings are unpacked and decorated with the section
# they belong to, before being printed.
/=/ {
s/^[[:space:]]*//
s/[[:space:]]*=[[:space:]]*/|/
G
s/\(.*\)\n\(.*\)/\2|\1/
p
}
this will convert the ini data into this flat format:
owner|name|John Doe
owner|organization|Acme Widgets Inc.
database|server|192.0.2.62
database|port|143
database|file|payroll.dat
so it'll be easier to parse using sed, awk or read by having section names in every line.
Credits & source: Configuration files for shell scripts, Michael Grünewald
Alternatively, you can use this project: chilladx/config-parser, a configuration parser using sed.
For people (like me) looking to read INI files from shell scripts (read shell, not bash) - I've knocked up the a little helper library which tries to do exactly that:
https://github.com/wallyhall/shini (MIT license, do with it as you please. I've linked above including it inline as the code is quite lengthy.)
It's somewhat more "complicated" than the simple sed lines suggested above - but works on a very similar basis.
Function reads in a file line-by-line - looking for section markers ([section]) and key/value declarations (key=value).
Ultimately you get a callback to your own function - section, key and value.
Here is my version, which parses sections and populates a global associative array g_iniProperties with it.
Note that this works only with bash v4.2 and higher.
function parseIniFile() { #accepts the name of the file to parse as argument ($1)
#declare syntax below (-gA) only works with bash 4.2 and higher
unset g_iniProperties
declare -gA g_iniProperties
currentSection=""
while read -r line
do
if [[ $line = [* ]] ; then
if [[ $line = [* ]] ; then
currentSection=$(echo $line | sed -e 's/\r//g' | tr -d "[]")
fi
else
if [[ $line = *=* ]] ; then
cleanLine=$(echo $line | sed -e 's/\r//g')
key=$currentSection.$(echo $cleanLine | awk -F: '{ st = index($0,"=");print substr($0,0,st-1)}')
value=$(echo $cleanLine | awk -F: '{ st = index($0,"=");print substr($0,st+1)}')
g_iniProperties[$key]=$value
fi
fi;
done < $1
}
And here is a sample code using the function above:
parseIniFile "/path/to/myFile.ini"
for key in "${!g_iniProperties[#]}"; do
echo "Found key/value $key = ${g_iniProperties[$key]}"
done
Yet another implementation using awk with a little more flexibility.
function parse_ini() {
cat /dev/stdin | awk -v section="$1" -v key="$2" '
BEGIN {
if (length(key) > 0) { params=2 }
else if (length(section) > 0) { params=1 }
else { params=0 }
}
match($0,/#/) { next }
match($0,/^\[(.+)\]$/){
current=substr($0, RSTART+1, RLENGTH-2)
found=current==section
if (params==0) { print current }
}
match($0,/(.+)=(.+)/) {
if (found) {
if (params==2 && key==$1) { print $3 }
if (params==1) { printf "%s=%s\n",$1,$3 }
}
}'
}
You can use calling passing between 0 and 2 params:
cat myfile1.ini myfile2.ini | parse_ini # List section names
cat myfile1.ini myfile2.ini | parse_ini 'my-section' # Prints keys and values from a section
cat myfile1.ini myfile2.ini | parse_ini 'my-section' 'my-key' # Print a single value
complex simplicity
ini file
test.ini
[section1]
name1=value1
name2=value2
[section2]
name1=value_1
name2 = value_2
bash script with read and execute
/bin/parseini
#!/bin/bash
set +a
while read p; do
reSec='^\[(.*)\]$'
#reNV='[ ]*([^ ]*)+[ ]*=(.*)' #Remove only spaces around name
reNV='[ ]*([^ ]*)+[ ]*=[ ]*(.*)' #Remove spaces around name and spaces before value
if [[ $p =~ $reSec ]]; then
section=${BASH_REMATCH[1]}
elif [[ $p =~ $reNV ]]; then
sNm=${section}_${BASH_REMATCH[1]}
sVa=${BASH_REMATCH[2]}
set -a
eval "$(echo "$sNm"=\""$sVa"\")"
set +a
fi
done < $1
then in another script I source the results of the command and can use any variables within
test.sh
#!/bin/bash
source parseini test.ini
echo $section2_name2
finally from command line the output is thus
# ./test.sh
value_2
Some of the answers don't respect comments. Some don't respect sections. Some recognize only one syntax (only ":" or only "="). Some Python answers fail on my machine because of differing captialization or failing to import the sys module. All are a bit too terse for me.
So I wrote my own, and if you have a modern Python, you can probably call this from your Bash shell. It has the advantage of adhering to some of the common Python coding conventions, and even provides sensible error messages and help. To use it, name it something like myconfig.py (do NOT call it configparser.py or it may try to import itself,) make it executable, and call it like
value=$(myconfig.py something.ini sectionname value)
Here's my code for Python 3.5 on Linux:
#!/usr/bin/env python3
# Last Modified: Thu Aug 3 13:58:50 PDT 2017
"""A program that Bash can call to parse an .ini file"""
import sys
import configparser
import argparse
if __name__ == '__main__':
parser = argparse.ArgumentParser(description="A program that Bash can call to parse an .ini file")
parser.add_argument("inifile", help="name of the .ini file")
parser.add_argument("section", help="name of the section in the .ini file")
parser.add_argument("itemname", help="name of the desired value")
args = parser.parse_args()
config = configparser.ConfigParser()
config.read(args.inifile)
print(config.get(args.section, args.itemname))
I wrote a quick and easy python script to include in my bash script.
For example, your ini file is called food.ini
and in the file you can have some sections and some lines:
[FRUIT]
Oranges = 14
Apples = 6
Copy this small 6 line Python script and save it as configparser.py
#!/usr/bin/python
import configparser
import sys
config = configparser.ConfigParser()
config.read(sys.argv[1])
print config.get(sys.argv[2],sys.argv[3])
Now, in your bash script you could do this for example.
OrangeQty=$(python configparser.py food.ini FRUIT Oranges)
or
ApplesQty=$(python configparser.py food.ini FRUIT Apples)
echo $ApplesQty
This presupposes:
you have Python installed
you have the configparser library installed (this should come with a std python installation)
Hope it helps
:¬)
The explanation to the answer for the one-liner sed.
[section1]
param1=123
param2=345
param3=678
[section2]
param1=abc
param2=def
param3=ghi
[section3]
param1=000
param2=111
param3=222
sed -nr "/^\[section2\]/ { :l /^\s*[^#].*/ p; n; /^\[/ q; b l; }" ./file.ini
To understand, it will be easier to format the line like this:
sed -nr "
# start processing when we found the word \"section2\"
/^\[section2\]/ { #the set of commands inside { } will be executed
#create a label \"l\" (https://www.grymoire.com/Unix/Sed.html#uh-58)
:l /^\s*[^#].*/ p;
# move on to the next line. For the first run it is the \"param1=abc\"
n;
# check if this line is beginning of new section. If yes - then exit.
/^\[/ q
#otherwise jump to the label \"l\"
b l
}
" file.ini
This script will get parameters as follow :
meaning that if your ini has :
pars_ini.ksh < path to ini file > < name of Sector in Ini file > < the name in name=value to return >
eg. how to call it :
[ environment ]
a=x
[ DataBase_Sector ]
DSN = something
Then calling :
pars_ini.ksh /users/bubu_user/parameters.ini DataBase_Sector DSN
this will retrieve the following "something"
the script "pars_ini.ksh" :
\#!/bin/ksh
\#INI_FILE=path/to/file.ini
\#INI_SECTION=TheSection
\# BEGIN parse-ini-file.sh
\# SET UP THE MINIMUM VARS FIRST
alias sed=/usr/local/bin/sed
INI_FILE=$1
INI_SECTION=$2
INI_NAME=$3
INI_VALUE=""
eval `sed -e 's/[[:space:]]*\=[[:space:]]*/=/g' \
-e 's/;.*$//' \
-e 's/[[:space:]]*$//' \
-e 's/^[[:space:]]*//' \
-e "s/^\(.*\)=\([^\"']*\)$/\1=\"\2\"/" \
< $INI_FILE \
| sed -n -e "/^\[$INI_SECTION\]/,/^\s*\[/{/^[^;].*\=.*/p;}"`
TEMP_VALUE=`echo "$"$INI_NAME`
echo `eval echo $TEMP_VALUE`
This implementation uses awk and has the following advantages:
Will only return the first matching entry
Ignores lines that start with a ;
Trims leading and trailing whitespace, but not internal whitespace
Formatted version:
awk -F '=' '/^\s*database_version\s*=/ {
sub(/^ +/, "", $2);
sub(/ +$/, "", $2);
print $2;
exit;
}' parameters.ini
One-liner:
awk -F '=' '/^\s*database_version\s*=/ { sub(/^ +/, "", $2); sub(/ +$/, "", $2); print $2; exit; }' parameters.ini
You can use a CSV parser xsv as parsing INI data.
cargo install xsv
$ cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
$ xsv select -d "=" - <<< "$( cat /etc/*release )" | xsv search --no-headers --select 1 "DISTRIB_CODENAME" | xsv select 2
xenial
or from a file.
$ xsv select -d "=" - file.ini | xsv search --no-headers --select 1 "DISTRIB_CODENAME" | xsv select 2
My version of the one-liner
#!/bin/bash
#Reader for MS Windows 3.1 Ini-files
#Usage: inireader.sh
# e.g.: inireader.sh win.ini ERRORS DISABLE
# would return value "no" from the section of win.ini
#[ERRORS]
#DISABLE=no
INIFILE=$1
SECTION=$2
ITEM=$3
cat $INIFILE | sed -n /^\[$SECTION\]/,/^\[.*\]/p | grep "^[:space:]*$ITEM[:space:]*=" | sed s/.*=[:space:]*//
Just finished writing my own parser. I tried to use various parser found here, none seems to work with both ksh93 (AIX) and bash (Linux).
It's old programming style - parsing line by line. Pretty fast since it used few external commands. A bit slower because of all the eval required for dynamic name of the array.
The ini support 3 special syntaxs:
includefile=ini file -->
Load an additionnal ini file. Useful for splitting ini in multiple files, or re-use some piece of configuration
includedir=directory -->
Same as includefile, but include a complete directory
includesection=section -->
Copy an existing section to the current section.
I used all thoses syntax to have pretty complex, re-usable ini file. Useful to install products when installing a new OS - we do that a lot.
Values can be accessed with ${ini[$section.$item]}. The array MUST be defined before calling this.
Have fun. Hope it's useful for someone else!
function Show_Debug {
[[ $DEBUG = YES ]] && echo "DEBUG $#"
}
function Fatal {
echo "$#. Script aborted"
exit 2
}
#-------------------------------------------------------------------------------
# This function load an ini file in the array "ini"
# The "ini" array must be defined in the calling program (typeset -A ini)
#
# It could be any array name, the default array name is "ini".
#
# There is heavy usage of "eval" since ksh and bash do not support
# reference variable. The name of the ini is passed as variable, and must
# be "eval" at run-time to work. Very specific syntax was used and must be
# understood before making any modifications.
#
# It complexify greatly the program, but add flexibility.
#-------------------------------------------------------------------------------
function Load_Ini {
Show_Debug "$0($#)"
typeset ini_file="$1"
# Name of the array to fill. By default, it's "ini"
typeset ini_array_name="${2:-ini}"
typeset section variable value line my_section file subsection value_array include_directory all_index index sections pre_parse
typeset LF="
"
if [[ ! -s $ini_file ]]; then
Fatal "The ini file is empty or absent in $0 [$ini_file]"
fi
include_directory=$(dirname $ini_file)
include_directory=${include_directory:-$(pwd)}
Show_Debug "include_directory=$include_directory"
section=""
# Since this code support both bash and ksh93, you cannot use
# the syntax "echo xyz|while read line". bash doesn't work like
# that.
# It forces the use of "<<<", introduced in bash and ksh93.
Show_Debug "Reading file $ini_file and putting the results in array $ini_array_name"
pre_parse="$(sed 's/^ *//g;s/#.*//g;s/ *$//g' <$ini_file | egrep -v '^$')"
while read line; do
if [[ ${line:0:1} = "[" ]]; then # Is the line starting with "["?
# Replace [section_name] to section_name by removing the first and last character
section="${line:1}"
section="${section%\]}"
eval "sections=\${$ini_array_name[sections_list]}"
sections="$sections${sections:+ }$section"
eval "$ini_array_name[sections_list]=\"$sections\""
Show_Debug "$ini_array_name[sections_list]=\"$sections\""
eval "$ini_array_name[$section.exist]=YES"
Show_Debug "$ini_array_name[$section.exist]='YES'"
else
variable=${line%%=*} # content before the =
value=${line#*=} # content after the =
if [[ $variable = includefile ]]; then
# Include a single file
Load_Ini "$include_directory/$value" "$ini_array_name"
continue
elif [[ $variable = includedir ]]; then
# Include a directory
# If the value doesn't start with a /, add the calculated include_directory
if [[ $value != /* ]]; then
value="$include_directory/$value"
fi
# go thru each file
for file in $(ls $value/*.ini 2>/dev/null); do
if [[ $file != *.ini ]]; then continue; fi
# Load a single file
Load_Ini "$file" "$ini_array_name"
done
continue
elif [[ $variable = includesection ]]; then
# Copy an existing section into the current section
eval "all_index=\"\${!$ini_array_name[#]}\""
# It's not necessarily fast. Need to go thru all the array
for index in $all_index; do
# Only if it is the requested section
if [[ $index = $value.* ]]; then
# Evaluate the subsection [section.subsection] --> subsection
subsection=${index#*.}
# Get the current value (source section)
eval "value_array=\"\${$ini_array_name[$index]}\""
# Assign the value to the current section
# The $value_array must be resolved on the second pass of the eval, so make sure the
# first pass doesn't resolve it (\$value_array instead of $value_array).
# It must be evaluated on the second pass in case there is special character like $1,
# or ' or " in it (code).
eval "$ini_array_name[$section.$subsection]=\"\$value_array\""
Show_Debug "$ini_array_name[$section.$subsection]=\"$value_array\""
fi
done
fi
# Add the value to the array
eval "current_value=\"\${$ini_array_name[$section.$variable]}\""
# If there's already something for this field, add it with the current
# content separated by a LF (line_feed)
new_value="$current_value${current_value:+$LF}$value"
# Assign the content
# The $new_value must be resolved on the second pass of the eval, so make sure the
# first pass doesn't resolve it (\$new_value instead of $new_value).
# It must be evaluated on the second pass in case there is special character like $1,
# or ' or " in it (code).
eval "$ini_array_name[$section.$variable]=\"\$new_value\""
Show_Debug "$ini_array_name[$section.$variable]=\"$new_value\""
fi
done <<< "$pre_parse"
Show_Debug "exit $0($#)\n"
}
When I use a password in base64, I put the separator ":" because the base64 string may has "=". For example (I use ksh):
> echo "Abc123" | base64
QWJjMTIzCg==
In parameters.ini put the line pass:QWJjMTIzCg==, and finally:
> PASS=`awk -F":" '/pass/ {print $2 }' parameters.ini | base64 --decode`
> echo "$PASS"
Abc123
If the line has spaces like "pass : QWJjMTIzCg== " add | tr -d ' ' to trim them:
> PASS=`awk -F":" '/pass/ {print $2 }' parameters.ini | tr -d ' ' | base64 --decode`
> echo "[$PASS]"
[Abc123]
This uses the system perl and clean regular expressions:
cat parameters.ini | perl -0777ne 'print "$1" if /\[\s*parameters\.ini\s*\][\s\S]*?\sdatabase_version\s*=\s*(.*)/'
The answer of "Karen Gabrielyan" among another answers was the best but in some environments we dont have awk, like typical busybox, i changed the answer by below code.
trim()
{
local trimmed="$1"
# Strip leading space.
trimmed="${trimmed## }"
# Strip trailing space.
trimmed="${trimmed%% }"
echo "$trimmed"
}
function parseIniFile() { #accepts the name of the file to parse as argument ($1)
#declare syntax below (-gA) only works with bash 4.2 and higher
unset g_iniProperties
declare -gA g_iniProperties
currentSection=""
while read -r line
do
if [[ $line = [* ]] ; then
if [[ $line = [* ]] ; then
currentSection=$(echo $line | sed -e 's/\r//g' | tr -d "[]")
fi
else
if [[ $line = *=* ]] ; then
cleanLine=$(echo $line | sed -e 's/\r//g')
key=$(trim $currentSection.$(echo $cleanLine | cut -d'=' -f1'))
value=$(trim $(echo $cleanLine | cut -d'=' -f2))
g_iniProperties[$key]=$value
fi
fi;
done < $1
}
If Python is available, the following will read all the sections, keys and values and save them in variables with their names following the format "[section]_[key]". Python can read .ini files properly, so we make use of it.
#!/bin/bash
eval $(python3 << EOP
from configparser import SafeConfigParser
config = SafeConfigParser()
config.read("config.ini"))
for section in config.sections():
for (key, val) in config.items(section):
print(section + "_" + key + "=\"" + val + "\"")
EOP
)
echo "Environment_type: ${Environment_type}"
echo "Environment_name: ${Environment_name}"
config.ini
[Environment]
type = DEV
name = D01
If using sections, this will do the job :
Example raw output :
$ ./settings
[section]
SETTING_ONE=this is setting one
SETTING_TWO=This is the second setting
ANOTHER_SETTING=This is another setting
Regexp parsing :
$ ./settings | sed -n -E "/^\[.*\]/{s/\[(.*)\]/\1/;h;n;};/^[a-zA-Z]/{s/#.*//;G;s/([^ ]*) *= *(.*)\n(.*)/\3_\1='\2'/;p;}"
section_SETTING_ONE='this is setting one'
section_SETTING_TWO='This is the second setting'
section_ANOTHER_SETTING='This is another setting'
Now all together :
$ eval "$(./settings | sed -n -E "/^\[.*\]/{s/\[(.*)\]/\1/;h;n;};/^[a-zA-Z]/{s/#.*//;G;s/([^ ]*) *= *(.*)\n(.*)/\3_\1='\2'/;p;}")"
$ echo $section_SETTING_TWO
This is the second setting
I have nice one-liner (assuimng you have php and jq installed):
cat file.ini | php -r "echo json_encode(parse_ini_string(file_get_contents('php://stdin'), true, INI_SCANNER_RAW));" | jq '.section.key'
This thread does not have enough solutions to choose from, thus here my solution, it does not require tools like sed or awk :
grep '^\[section\]' -A 999 config.ini | tail -n +2 | grep -B 999 '^\[' | head -n -1 | grep '^key' | cut -d '=' -f 2
If your are to expect sections with more than 999 lines, feel free to adapt the example above. Note that you may want to trim the resulting value, to remove spaces or a comment string after the value. Remove the ^ if you need to match keys that do not start at the beginning of the line, as in the example of the question. Better, match explicitly for white spaces and tabs, in such a case.
If you have multiple values in a given section you want to read, but want to avoid reading the file multiple times:
CONFIG_SECTION=$(grep '^\[section\]' -A 999 config.ini | tail -n +2 | grep -B 999 '^\[' | head -n -1)
KEY1=$(echo ${CONFIG_SECTION} | tr ' ' '\n' | grep key1 | cut -d '=' -f 2)
echo "KEY1=${KEY1}"
KEY2=$(echo ${CONFIG_SECTION} | tr ' ' '\n' | grep key2 | cut -d '=' -f 2)
echo "KEY2=${KEY2}"

bash: how can I read text in file into string, modify it and save it another file?

I have a file (imaginary):
test() {
echo ${%%NUMBER%%}
}
I need:
Read it into string variable
Replace %%NUMBER%% with number
Save it to another file, maintaining the multi-line architecture.
How I do it:
#!/bin/bash
# Full path of this script
FILE=`readlink -f "${BASH_SOURCE[0]}"`
# This directory path
DIR=`dirname "${FILE}"`
repl() {
STRING=$(cat $DIR/skel.txt)
STRING=$(echo $STRING | sed "s/%%NUMBER%%/$1/")
echo $STRING
}
# try it
repl 50 > ./out.sh
# tried as well:
# repl 50 | tee ./out.sh
# echo "$(repl 50)" > ./out.sh
# STRING=$(echo -e $STRING | sed "s/%%NUMBER%%/$1/")
But I always get everything in one line in out.sh file. Need it to stay multiline, as in source.
Thanks.
Try this:
repl() {
sed "s/%%NUMBER%%/$1/" "$DIR/skel.txt"
}
This is far more efficient, and won't eat your precious newlines.

Using sed command to

I'm trying to be able to read a file, replace a variable or instead add it at the bottom if it hasn't been already specified.
I've had a bit of help to get this far:
#!/bin/bash
function replaceappend() {
if ! sed "/$2/{s//$3/;h};"'${x;/./{x;q0};x;q1}' $1
then
echo "$3" >> $1
fi
}
replaceappend "/etc/ssh/sshd_config" "Port 22" "Port 123"
However, after running this script the contents of the original file seem to be untouched, and remain at Port 22 with nothing appended.
In this example it's using a speicfied exit code on sed using the q flag to see if it finds it or not, and then appending it if not.
Can anyone see why this code may not work?
I think this is what you're trying to do:
$ cat tst.sh
function replaceappend() {
awk -v old="$2" -v new="$3" '
sub(old,new) { replaced=1 }
{ print }
END { if (!replaced) print new }
' "$1" > /usr/tmp/tmp$$ &&
mv /usr/tmp/tmp$$ "$1"
}
replaceappend file "Port 22" "Port 123"
replaceappend file "Port 22" "Port 123"
$ cat file
line 1
Port 22
line 3
Port 71
line 5
$ ./tst.sh
$ cat file
line 1
Port 123
line 3
Port 71
line 5
Port 123
This might work for you (GNU sed & bash):
function replaceappend() {
sed '/'"$2"'/{s//'"$3"'/;h};$!b;x;/./{x;b};x;a'"$3" $1
}
The function uses the original sed statement but instead of returning an exit code at the end of the file it checks the hold space (which has been used as a flag to mark if a substitution has taken place) and either does nothing when a substitution has already taken place or appends the required string to the end of the file when the substitution has failed.

echo and cat-supresses the new line characters

Below is the example.I can see that when i use echo with cat it suppresses the new line characters.Is this the expected behaviour?I am working on solaris unix.
.262> cat temp2.txt
20110801
20110802
20110803
20110804
20110805
20110808
> echo `cat temp2.txt `
20110801 20110802 20110803 20110804 20110805 20110808
Yes this is the expected behaviour.
But as "Mark Reed" suggested you can keep the white space by using quotes:
echo "$(cat temp2.txt)"
Yes this is expected behavior.
I don't know of any shell that doesn't do it.
It is documented in bash:
$ man bash | awk '/Command Substitution/ { p = 1 } /Arithmetic Expansion/ { p = 0 } { if (p) print; }'
In zsh:
$ man zshall | awk '/COMMAND SUBSTITUTION/ {p=1} /ARITHMETIC EXPANSION/ {p=0} { if (p) print }'
(Edit: I removed the output of the command lines as they are pointless, as pointed out by #sehe in the comment)

How to replace ${} placeholders in a text file?

I want to pipe the output of a "template" file into MySQL, the file having variables like ${dbName} interspersed. What is the command line utility to replace these instances and dump the output to standard output?
The input file is considered to be safe, but faulty substitution definitions could exist. Performing the replacement should avoid performing unintended code execution.
Update
Here is a solution from yottatsa on a similar question that only does replacement for variables like $VAR or ${VAR}, and is a brief one-liner
i=32 word=foo envsubst < template.txt
Of course if i and word are in your environment, then it is just
envsubst < template.txt
On my Mac it looks like it was installed as part of gettext and from MacGPG2
Old Answer
Here is an improvement to the solution from mogsie on a similar question, my solution does not require you to escale double quotes, mogsie's does, but his is a one liner!
eval "cat <<EOF
$(<template.txt)
EOF
" 2> /dev/null
The power on these two solutions is that you only get a few types of shell expansions that don't occur normally $((...)), `...`, and $(...), though backslash is an escape character here, but you don't have to worry that the parsing has a bug, and it does multiple lines just fine.
Sed!
Given template.txt:
The number is ${i}
The word is ${word}
we just have to say:
sed -e "s/\${i}/1/" -e "s/\${word}/dog/" template.txt
Thanks to Jonathan Leffler for the tip to pass multiple -e arguments to the same sed invocation.
Use /bin/sh. Create a small shell script that sets the variables, and then parse the template using the shell itself. Like so (edit to handle newlines correctly):
File template.txt:
the number is ${i}
the word is ${word}
File script.sh:
#!/bin/sh
#Set variables
i=1
word="dog"
#Read in template one line at the time, and replace variables (more
#natural (and efficient) way, thanks to Jonathan Leffler).
while read line
do
eval echo "$line"
done < "./template.txt"
Output:
#sh script.sh
the number is 1
the word is dog
I was thinking about this again, given the recent interest, and I think that the tool that I was originally thinking of was m4, the macro processor for autotools. So instead of the variable I originally specified, you'd use:
$echo 'I am a DBNAME' | m4 -DDBNAME="database name"
Create rendertemplate.sh:
#!/usr/bin/env bash
eval "echo \"$(cat $1)\""
And template.tmpl:
Hello, ${WORLD}
Goodbye, ${CHEESE}
Render the template:
$ export WORLD=Foo
$ CHEESE=Bar ./rendertemplate.sh template.tmpl
Hello, Foo
Goodbye, Bar
template.txt
Variable 1 value: ${var1}
Variable 2 value: ${var2}
data.sh
#!/usr/bin/env bash
declare var1="value 1"
declare var2="value 2"
parser.sh
#!/usr/bin/env bash
# args
declare file_data=$1
declare file_input=$2
declare file_output=$3
source $file_data
eval "echo \"$(< $file_input)\"" > $file_output
./parser.sh data.sh template.txt parsed_file.txt
parsed_file.txt
Variable 1 value: value 1
Variable 2 value: value 2
Here's a robust Bash function that - despite using eval - should be safe to use.
All ${varName} variable references in the input text are expanded based on the calling shell's variables.
Nothing else is expanded: neither variable references whose names are not enclosed in {...} (such as $varName), nor command substitutions ($(...) and legacy syntax `...`), nor arithmetic substitutions ($((...)) and legacy syntax $[...]).
To treat a $ as a literal, \-escape it; e.g.:\${HOME}
Note that input is only accepted via stdin.
Example:
$ expandVarsStrict <<<'$HOME is "${HOME}"; `date` and \$(ls)' # only ${HOME} is expanded
$HOME is "/Users/jdoe"; `date` and $(ls)
Function source code:
expandVarsStrict(){
local line lineEscaped
while IFS= read -r line || [[ -n $line ]]; do # the `||` clause ensures that the last line is read even if it doesn't end with \n
# Escape ALL chars. that could trigger an expansion..
IFS= read -r -d '' lineEscaped < <(printf %s "$line" | tr '`([$' '\1\2\3\4')
# ... then selectively reenable ${ references
lineEscaped=${lineEscaped//$'\4'{/\${}
# Finally, escape embedded double quotes to preserve them.
lineEscaped=${lineEscaped//\"/\\\"}
eval "printf '%s\n' \"$lineEscaped\"" | tr '\1\2\3\4' '`([$'
done
}
The function assumes that no 0x1, 0x2, 0x3, and 0x4 control characters are present in the input, because those chars. are used internally - since the function processes text, that should be a safe assumption.
here's my solution with perl based on former answer, replaces environment variables:
perl -p -e 's/\$\{(\w+)\}/(exists $ENV{$1}?$ENV{$1}:"missing variable $1")/eg' < infile > outfile
I would suggest using something like Sigil:
https://github.com/gliderlabs/sigil
It is compiled to a single binary, so it's extremely easy to install on systems.
Then you can do a simple one-liner like the following:
cat my-file.conf.template | sigil -p $(env) > my-file.conf
This is much safer than eval and easier then using regex or sed
Here is a way to get the shell to do the substitution for you, as if the contents of the file were instead typed between double quotes.
Using the example of template.txt with contents:
The number is ${i}
The word is ${word}
The following line will cause the shell to interpolate the contents of template.txt and write the result to standard out.
i='1' word='dog' sh -c 'echo "'"$(cat template.txt)"'"'
Explanation:
i and word are passed as environment variables scopped to the execution of sh.
sh executes the contents of the string it is passed.
Strings written next to one another become one string, that string is:
'echo "' + "$(cat template.txt)" + '"'
Since the substitution is between ", "$(cat template.txt)" becomes the output of cat template.txt.
So the command executed by sh -c becomes:
echo "The number is ${i}\nThe word is ${word}",
where i and word are the specified environment variables.
If you are open to using Perl, that would be my suggestion. Although there are probably some sed and/or AWK experts that probably know how to do this much easier. If you have a more complex mapping with more than just dbName for your replacements you could extend this pretty easily, but you might just as well put it into a standard Perl script at that point.
perl -p -e 's/\$\{dbName\}/testdb/s' yourfile | mysql
A short Perl script to do something slightly more complicated (handle multiple keys):
#!/usr/bin/env perl
my %replace = ( 'dbName' => 'testdb', 'somethingElse' => 'fooBar' );
undef $/;
my $buf = <STDIN>;
$buf =~ s/\$\{$_\}/$replace{$_}/g for keys %replace;
print $buf;
If you name the above script as replace-script, it could then be used as follows:
replace-script < yourfile | mysql
file.tpl:
The following bash function should only replace ${var1} syntax and ignore
other shell special chars such as `backticks` or $var2 or "double quotes".
If I have missed anything - let me know.
script.sh:
template(){
# usage: template file.tpl
while read -r line ; do
line=${line//\"/\\\"}
line=${line//\`/\\\`}
line=${line//\$/\\\$}
line=${line//\\\${/\${}
eval "echo \"$line\"";
done < ${1}
}
var1="*replaced*"
var2="*not replaced*"
template file.tpl > result.txt
I found this thread while wondering the same thing. It inspired me to this (careful with the backticks)
$ echo $MYTEST
pass!
$ cat FILE
hello $MYTEST world
$ eval echo `cat FILE`
hello pass! world
Lots of choices here, but figured I'd toss mine on the heap. It is perl based, only targets variables of the form ${...}, takes the file to process as an argument and outputs the converted file on stdout:
use Env;
Env::import();
while(<>) { $_ =~ s/(\${\w+})/$1/eeg; $text .= $_; }
print "$text";
Of course I'm not really a perl person, so there could easily be a fatal flaw (works for me though).
It can be done in bash itself if you have control of the configuration file format. You just need to source (".") the configuration file rather than subshell it. That ensures the variables are created in the context of the current shell (and continue to exist) rather than the subshell (where the variable disappear when the subshell exits).
$ cat config.data
export parm_jdbc=jdbc:db2://box7.co.uk:5000/INSTA
export parm_user=pax
export parm_pwd=never_you_mind
$ cat go.bash
. config.data
echo "JDBC string is " $parm_jdbc
echo "Username is " $parm_user
echo "Password is " $parm_pwd
$ bash go.bash
JDBC string is jdbc:db2://box7.co.uk:5000/INSTA
Username is pax
Password is never_you_mind
If your config file cannot be a shell script, you can just 'compile' it before executing thus (the compilation depends on your input format).
$ cat config.data
parm_jdbc=jdbc:db2://box7.co.uk:5000/INSTA # JDBC URL
parm_user=pax # user name
parm_pwd=never_you_mind # password
$ cat go.bash
cat config.data
| sed 's/#.*$//'
| sed 's/[ \t]*$//'
| sed 's/^[ \t]*//'
| grep -v '^$'
| sed 's/^/export '
>config.data-compiled
. config.data-compiled
echo "JDBC string is " $parm_jdbc
echo "Username is " $parm_user
echo "Password is " $parm_pwd
$ bash go.bash
JDBC string is jdbc:db2://box7.co.uk:5000/INSTA
Username is pax
Password is never_you_mind
In your specific case, you could use something like:
$ cat config.data
export p_p1=val1
export p_p2=val2
$ cat go.bash
. ./config.data
echo "select * from dbtable where p1 = '$p_p1' and p2 like '$p_p2%' order by p1"
$ bash go.bash
select * from dbtable where p1 = 'val1' and p2 like 'val2%' order by p1
Then pipe the output of go.bash into MySQL and voila, hopefully you won't destroy your database :-).
In place perl editing of potentially multiple files, with backups.
perl -e 's/\$\{([^}]+)\}/defined $ENV{$1} ? $ENV{$1} : ""/eg' \
-i.orig \
-p config/test/*
I created a shell templating script named shtpl. My shtpl uses a jinja-like syntax which, now that I use ansible a lot, I'm pretty familiar with:
$ cat /tmp/test
{{ aux=4 }}
{{ myarray=( a b c d ) }}
{{ A_RANDOM=$RANDOM }}
$A_RANDOM
{% if $(( $A_RANDOM%2 )) == 0 %}
$A_RANDOM is even
{% else %}
$A_RANDOM is odd
{% endif %}
{% if $(( $A_RANDOM%2 )) == 0 %}
{% for n in 1 2 3 $aux %}
\$myarray[$((n-1))]: ${myarray[$((n-1))]}
/etc/passwd field #$n: $(grep $USER /etc/passwd | cut -d: -f$n)
{% endfor %}
{% else %}
{% for n in {1..4} %}
\$myarray[$((n-1))]: ${myarray[$((n-1))]}
/etc/group field #$n: $(grep ^$USER /etc/group | cut -d: -f$n)
{% endfor %}
{% endif %}
$ ./shtpl < /tmp/test
6535
6535 is odd
$myarray[0]: a
/etc/group field #1: myusername
$myarray[1]: b
/etc/group field #2: x
$myarray[2]: c
/etc/group field #3: 1001
$myarray[3]: d
/etc/group field #4:
More info on my github
To me this is the easiest and most powerful solution, you can even include other templates using the same command eval echo "$(<template.txt):
Example with nested template
create the template files, the variables are in regular bash syntax ${VARIABLE_NAME} or $VARIABLE_NAME
you have to escape special characters with \ in your templates otherwhise they will be interpreted by eval.
template.txt
Hello ${name}!
eval echo $(<nested-template.txt)
nested-template.txt
Nice to have you here ${name} :\)
create source file
template.source
declare name=royman
parse the template
source template.source && eval echo "$(<template.txt)"
the output
Hello royman!
Nice to have you here royman :)
envsubst
please don't use anything else (ie. don't eval)

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