I'am trying to get the first character of each string using regex and BASH_REMATCH in shell script.
My input text file contain :
config_text = STACK OVER FLOW
The strings STACK OVER FLOW must be uppercase like that.
My output should be something like this :
SOF
My code for now is :
var = config_text
values=$(grep $var test_file.txt | tr -s ' ' '\n' | cut -c 1)
if [[ $values =~ [=(.*)]]; then
echo $values
fi
As you can see I'am using tr and cut but I'am looking to replace them with only BASH_REMATCH because these two commands have been reported in many links as not functional on MacOs.
I tried something like this :
var = config_text
values=$(grep $var test_file.txt)
if [[ $values =~ [=(.*)(\b[a-zA-Z])]]; then
echo $values
fi
VALUES as I explained should be :
S O F
But it seems \b does not work on shell script.
Anyone have an idea how to get my desired output with BASH_REMATCH ONLY.
Thanks in advance for any help.
A generic BASH_REMATCH solution handling any number of words and any separator.
local input="STACK OVER FLOW" pattern='([[:upper:]]+)([^[:upper:]]*)' result=""
while [[ $input =~ $pattern ]]; do
result+="${BASH_REMATCH[1]::1}${BASH_REMATCH[2]}"
input="${input:${#BASH_REMATCH[0]}}"
done
echo "$result"
# Output: "S O F"
Bash's regexes are kind of cumbersome if you don't know how many words there are in the input string. How's this instead?
config_text="STACK OVER FLOW"
sed 's/\([^[:space:]]\)[^[:space:]]*/\1/g' <<<"$config_text"
First Put a valid shebang and paste your script at https://shellcheck.net for validation/recommendation.
With the assumption that the line starts with config and ends with FLOW e.g.
config_text = STACK OVER FLOW
Now the script.
#!/usr/bin/env bash
values="config_text = STACK OVER FLOW"
regexp="config_text = ([[:upper:]]{1})[^ ]+ ([[:upper:]]{1})[^ ]+ ([[:upper:]]{1}).+$"
while IFS= read -r line; do
[[ "$line" = "$values" && "$values" =~ $regexp ]] &&
printf '%s %s %s\n' "${BASH_REMATCH[1]}" "${BASH_REMATCH[2]}" "${BASH_REMATCH[3]}"
done < test_file.txt
If there is Only one line or the target string/pattern is at the first line of the test_file.txt, the while loop is not needed.
#!/usr/bin/env bash
values="config_text = STACK OVER FLOW"
regexp="config_text = ([[:upper:]]{1})[^ ]+ ([[:upper:]]{1})[^ ]+ ([[:upper:]]{1}).+$"
IFS= read -r line < test_file.txt
[[ "$line" = "$values" && "$values" =~ $regexp ]] &&
printf '%s %s %s\n' "${BASH_REMATCH[1]}" "${BASH_REMATCH[2]}" "${BASH_REMATCH[3]}"
Make sure you have and running/using Bashv4+ since MacOS, defaults to Bashv3
See How can I read a file (data stream, variable) line-by-line (and/or field-by-field)?
Another option rather than bash regex would be to utilize bash parameter expansion substring ${parameter:offset:length} to extract the desired characters:
$ read -ra arr <text.file ; printf "%s%s%s\n" "${arr[2]:0:1}" "${arr[3]:0:1}" "${arr[4]:0:1}"
SOF
I have an .xcconfig file that I want to access via the terminal to access variables in the file. Is there a command or is there some way to do this? For example I have a variable called Build_Code = 1234. How would I access that?
Create a script to read the value of a variable.
Ex: .xconfig
var1 = value1
var2 = value2
get_value.bash
#!/bin/bash
#
# get_value.bash <file> <variable>
#
usage()
{
echo "Usage: get_value.bash <file> <variable>"
exit 1
}
#################################################
# Arguments
if [[ $# -eq 2 ]]
then
file="$1"
var="$2"
else
usage
fi
# Check if the file exists
if [[ ! -f "$file" ]]
then
echo "ERROR: file $file does not exist."
exit 2
fi
# Get the variable's value
grep -w "$var" "$file" | cut -d'=' -f2 | tr -d ' '
This simple version assumes the format of the lines is VARIABLE\s*=\s*VALUE.
The tr is to remove spaces around the value.
The VALUE cannot contain spaces.
The <file> argument could be hard coded if you will only ever check .xconfig
Many other solutions could be conceived, depending on the exact requirements, but this does the basic need you put in your question.
Through some here help I was to get only the text between quotation marks in a file like so:
text undefined but text
something something text something
shouldfindthis "dolphin"
butalsothis "elephant"
by doing:
i=0
regex='(".*?")' # Match all what is between "
while read line # read file line by line
do
if [[ $line =~ $regex ]]; then # If regex match
vars[$i]="${BASH_REMATCH[1]}" # store capturing group in a array
i=$((i + 1))
fi
done < txt # file "txt"
# Print what we found
if [ -v "vars" ]; then # if we found something , "vars" will exist
for var in "${vars[#]}"
do
echo "$var"
done
fi
Yielding an output:
$ ./script.sh
"dolphin"
"elephant"
Is there a way to mark these as variables? As such that dolphin is $text1 and elephant is $text2? in doing so that I can replace only the text within the paranthasis?
First: Using arrays, as your code already does, is the best-practice approach. Don't change it. However, if you really want to write to separate variables rather than array, then replace:
vars[$i]="${BASH_REMATCH[1]}" # this could also be vars+=( "${BASH_REMATCH[1]}" )
...with...
printf -v "text$i" '%s' "${BASH_REMATCH[1]}"
If you want to eliminate the quotes themselves, move them outside the grouping operator in your regex:
regex='"([^"]*)"'
I'm attempting to read a config file that is formatted as follows:
USER = username
TARGET = arrows
I realize that if I got rid of the spaces, I could simply source the config file, but for security reasons I'm trying to avoid that. I know there is a way to read the config file line by line. I think the process is something like:
Read lines into an array
Filter out all of the lines that start with #
search for the variable names in the array
After that I'm lost. Any and all help would be greatly appreciated. I've tried something like this with no success:
backup2.config>cat ~/1
grep '^[^#].*' | while read one two;do
echo $two
done
I pulled that from a forum post I found, just not sure how to modify it to fit my needs since I'm so new to shell scripting.
http://www.linuxquestions.org/questions/programming-9/bash-shell-program-read-a-configuration-file-276852/
Would it be possible to automatically assign a variable by looping through both arrays?
for (( i = 0 ; i < ${#VALUE[#]} ; i++ ))
do
"${NAME[i]}"=VALUE[i]
done
echo $USER
Such that calling $USER would output "username"? The above code isn't working but I know the solution is something similar to that.
The following script iterates over each line in your input file (vars in my case) and does a pattern match against =. If the equal sign is found it will use Parameter Expansion to parse out the variable name from the value. It then stores each part in it's own array, name and value respectively.
#!/bin/bash
i=0
while read line; do
if [[ "$line" =~ ^[^#]*= ]]; then
name[i]=${line%% =*}
value[i]=${line#*= }
((i++))
fi
done < vars
echo "total array elements: ${#name[#]}"
echo "name[0]: ${name[0]}"
echo "value[0]: ${value[0]}"
echo "name[1]: ${name[1]}"
echo "value[1]: ${value[1]}"
echo "name array: ${name[#]}"
echo "value array: ${value[#]}"
Input
$ cat vars
sdf
USER = username
TARGET = arrows
asdf
as23
Output
$ ./varscript
total array elements: 2
name[0]: USER
value[0]: username
name[1]: TARGET
value[1]: arrows
name array: USER TARGET
value array: username arrows
First, USER is a shell environment variable, so it might be better if you used something else. Using lowercase or mixed case variable names is a way to avoid name collisions.
#!/bin/bash
configfile="/path/to/file"
shopt -s extglob
while IFS='= ' read lhs rhs
do
if [[ $lhs != *( )#* ]]
then
# you can test for variables to accept or other conditions here
declare $lhs=$rhs
fi
done < "$configfile"
This sets the vars in your file to the value associated with it.
echo "Username: $USER, Target: $TARGET"
would output
Username: username, Target: arrows
Another way to do this using keys and values is with an associative array:
Add this line before the while loop:
declare -A settings
Remove the declare line inside the while loop and replace it with:
settings[$lhs]=$rhs
Then:
# set keys
user=USER
target=TARGET
# access values
echo "Username: ${settings[$user]}, Target: ${settings[$target]}"
would output
Username: username, Target: arrows
I have a script which only takes a very limited number of settings, and processes them one at a time, so I've adapted SiegeX's answer to whitelist the settings I care about and act on them as it comes to them.
I've also removed the requirement for spaces around the = in favour of ignoring any that exist using the trim function from another answer.
function trim()
{
local var=$1;
var="${var#"${var%%[![:space:]]*}"}"; # remove leading whitespace characters
var="${var%"${var##*[![:space:]]}"}"; # remove trailing whitespace characters
echo -n "$var";
}
while read line; do
if [[ "$line" =~ ^[^#]*= ]]; then
setting_name=$(trim "${line%%=*}");
setting_value=$(trim "${line#*=}");
case "$setting_name" in
max_foos)
prune_foos $setting_value;
;;
max_bars)
prune_bars $setting_value;
;;
*)
echo "Unrecognised setting: $setting_name";
;;
esac;
fi
done <"$config_file";
Thanks SiegeX. I think the later updates you mentioned does not reflect in this URL.
I had to edit the regex to remove the quotes to get it working. With quotes, array returned is empty.
i=0
while read line; do
if [[ "$line" =~ ^[^#]*= ]]; then
name[i]=${line%% =*}
value[i]=${line##*= }
((i++))
fi
done < vars
A still better version is .
i=0
while read line; do
if [[ "$line" =~ ^[^#]*= ]]; then
name[i]=`echo $line | cut -d'=' -f 1`
value[i]=`echo $line | cut -d'=' -f 2`
((i++))
fi
done < vars
The first version is seen to have issues if there is no space before and after "=" in the config file. Also if the value is missing, i see that the name and value are populated as same. The second version does not have any of these. In addition it trims out unwanted leading and trailing spaces.
This version reads values that can have = within it. Earlier version splits at first occurance of =.
i=0
while read line; do
if [[ "$line" =~ ^[^#]*= ]]; then
name[i]=`echo $line | cut -d'=' -f 1`
value[i]=`echo $line | cut -d'=' -f 2-`
((i++))
fi
done < vars
I have a bash script that is being used in a CGI. The CGI sets the $QUERY_STRING environment variable by reading everything after the ? in the URL. For example, http://example.com?a=123&b=456&c=ok sets QUERY_STRING=a=123&b=456&c=ok.
Somewhere I found the following ugliness:
b=$(echo "$QUERY_STRING" | sed -n 's/^.*b=\([^&]*\).*$/\1/p' | sed "s/%20/ /g")
which will set $b to whatever was found in $QUERY_STRING for b. However, my script has grown to have over ten input parameters. Is there an easier way to automatically convert the parameters in $QUERY_STRING into environment variables usable by bash?
Maybe I'll just use a for loop of some sort, but it'd be even better if the script was smart enough to automatically detect each parameter and maybe build an array that looks something like this:
${parm[a]}=123
${parm[b]}=456
${parm[c]}=ok
How could I write code to do that?
Try this:
saveIFS=$IFS
IFS='=&'
parm=($QUERY_STRING)
IFS=$saveIFS
Now you have this:
parm[0]=a
parm[1]=123
parm[2]=b
parm[3]=456
parm[4]=c
parm[5]=ok
In Bash 4, which has associative arrays, you can do this (using the array created above):
declare -A array
for ((i=0; i<${#parm[#]}; i+=2))
do
array[${parm[i]}]=${parm[i+1]}
done
which will give you this:
array[a]=123
array[b]=456
array[c]=ok
Edit:
To use indirection in Bash 2 and later (using the parm array created above):
for ((i=0; i<${#parm[#]}; i+=2))
do
declare var_${parm[i]}=${parm[i+1]}
done
Then you will have:
var_a=123
var_b=456
var_c=ok
You can access these directly:
echo $var_a
or indirectly:
for p in a b c
do
name="var$p"
echo ${!name}
done
If possible, it's better to avoid indirection since it can make code messy and be a source of bugs.
you can break $QUERY down using IFS. For example, setting it to &
$ QUERY="a=123&b=456&c=ok"
$ echo $QUERY
a=123&b=456&c=ok
$ IFS="&"
$ set -- $QUERY
$ echo $1
a=123
$ echo $2
b=456
$ echo $3
c=ok
$ array=($#)
$ for i in "${array[#]}"; do IFS="=" ; set -- $i; echo $1 $2; done
a 123
b 456
c ok
And you can save to a hash/dictionary in Bash 4+
$ declare -A hash
$ for i in "${array[#]}"; do IFS="=" ; set -- $i; hash[$1]=$2; done
$ echo ${hash["b"]}
456
Please don't use the evil eval junk.
Here's how you can reliably parse the string and get an associative array:
declare -A param
while IFS='=' read -r -d '&' key value && [[ -n "$key" ]]; do
param["$key"]=$value
done <<<"${QUERY_STRING}&"
If you don't like the key check, you could do this instead:
declare -A param
while IFS='=' read -r -d '&' key value; do
param["$key"]=$value
done <<<"${QUERY_STRING:+"${QUERY_STRING}&"}"
Listing all the keys and values from the array:
for key in "${!param[#]}"; do
echo "$key: ${param[$key]}"
done
I packaged the sed command up into another script:
$cat getvar.sh
s='s/^.*'${1}'=\([^&]*\).*$/\1/p'
echo $QUERY_STRING | sed -n $s | sed "s/%20/ /g"
and I call it from my main cgi as:
id=`./getvar.sh id`
ds=`./getvar.sh ds`
dt=`./getvar.sh dt`
...etc, etc - you get idea.
works for me even with a very basic busybox appliance (my PVR in this case).
To converts the contents of QUERY_STRING into bash variables use the following command:
eval $(echo ${QUERY_STRING//&/;})
The inner step, echo ${QUERY_STRING//&/;}, substitutes all ampersands with semicolons producing a=123;b=456;c=ok which the eval then evaluates into the current shell.
The result can then be used as bash variables.
echo $a
echo $b
echo $c
The assumptions are:
values will never contain '&'
values will never contain ';'
QUERY_STRING will never contain malicious code
While the accepted answer is probably the most beautiful one, there might be cases where security is super-important, and it needs to be also well-visible from your script.
In such a case, first I wouldn't use bash for the task, but if it should be done on some reason, it might be better to avoid these new array - dictionary features, because you can't be sure, how exactly are they escaped.
In this case, the good old primitive solutions might work:
QS="${QUERY_STRING}"
while [ "${QS}" != "" ]
do
nameval="${QS%%&*}"
QS="${QS#$nameval}"
QS="${QS#&}"
name="${nameval%%=*}"
val="${nameval#$name}"
val="${nameval#=}"
# and here we have $name and $val as names and values
# ...
done
This iterates on the name-value pairs of the QUERY_STRING, and there is no way to circumvent it with any tricky escape sequence - the " is a very strong thing in bash, except a single variable name substitution, which is fully controlled by us, nothing can be tricked.
Furthermore, you can inject your own processing code into "# ...". This enables you to allow only your own, well-defined (and, ideally, short) list of the allowed variable names. Needless to say, LD_PRELOAD shouldn't be one of them. ;-)
Furthermore, no variable will be exported, and exclusively QS, nameval, name and val is used.
Following the correct answer, I've done myself some changes to support array variables like in this other question. I added also a decode function of which I can not find the author to give some credit.
Code appears somewhat messy, but it works. Changes and other recommendations would be greatly appreciated.
function cgi_decodevar() {
[ $# -ne 1 ] && return
local v t h
# replace all + with whitespace and append %%
t="${1//+/ }%%"
while [ ${#t} -gt 0 -a "${t}" != "%" ]; do
v="${v}${t%%\%*}" # digest up to the first %
t="${t#*%}" # remove digested part
# decode if there is anything to decode and if not at end of string
if [ ${#t} -gt 0 -a "${t}" != "%" ]; then
h=${t:0:2} # save first two chars
t="${t:2}" # remove these
v="${v}"`echo -e \\\\x${h}` # convert hex to special char
fi
done
# return decoded string
echo "${v}"
return
}
saveIFS=$IFS
IFS='=&'
VARS=($QUERY_STRING)
IFS=$saveIFS
for ((i=0; i<${#VARS[#]}; i+=2))
do
curr="$(cgi_decodevar ${VARS[i]})"
next="$(cgi_decodevar ${VARS[i+2]})"
prev="$(cgi_decodevar ${VARS[i-2]})"
value="$(cgi_decodevar ${VARS[i+1]})"
array=${curr%"[]"}
if [ "$curr" == "$next" ] && [ "$curr" != "$prev" ] ;then
j=0
declare var_${array}[$j]="$value"
elif [ $i -gt 1 ] && [ "$curr" == "$prev" ]; then
j=$((j + 1))
declare var_${array}[$j]="$value"
else
declare var_$curr="$value"
fi
done
I would simply replace the & to ;. It will become to something like:
a=123;b=456;c=ok
So now you need just evaluate and read your vars:
eval `echo "${QUERY_STRING}"|tr '&' ';'`
echo $a
echo $b
echo $c
A nice way to handle CGI query strings is to use Haserl which acts as a wrapper around your Bash cgi script, and offers convenient and secure query string parsing.
To bring this up to date, if you have a recent Bash version then you can achieve this with regular expressions:
q="$QUERY_STRING"
re1='^(\w+=\w+)&?'
re2='^(\w+)=(\w+)$'
declare -A params
while [[ $q =~ $re1 ]]; do
q=${q##*${BASH_REMATCH[0]}}
[[ ${BASH_REMATCH[1]} =~ $re2 ]] && params+=([${BASH_REMATCH[1]}]=${BASH_REMATCH[2]})
done
If you don't want to use associative arrays then just change the penultimate line to do what you want. For each iteration of the loop the parameter is in ${BASH_REMATCH[1]} and its value is in ${BASH_REMATCH[2]}.
Here is the same thing as a function in a short test script that iterates over the array outputs the query string's parameters and their values
#!/bin/bash
QUERY_STRING='foo=hello&bar=there&baz=freddy'
get_query_string() {
local q="$QUERY_STRING"
local re1='^(\w+=\w+)&?'
local re2='^(\w+)=(\w+)$'
while [[ $q =~ $re1 ]]; do
q=${q##*${BASH_REMATCH[0]}}
[[ ${BASH_REMATCH[1]} =~ $re2 ]] && eval "$1+=([${BASH_REMATCH[1]}]=${BASH_REMATCH[2]})"
done
}
declare -A params
get_query_string params
for k in "${!params[#]}"
do
v="${params[$k]}"
echo "$k : $v"
done
Note the parameters end up in the array in reverse order (it's associative so that shouldn't matter).
why not this
$ echo "${QUERY_STRING}"
name=carlo&last=lanza&city=pfungen-CH
$ saveIFS=$IFS
$ IFS='&'
$ eval $QUERY_STRING
$ IFS=$saveIFS
now you have this
name = carlo
last = lanza
city = pfungen-CH
$ echo "name is ${name}"
name is carlo
$ echo "last is ${last}"
last is lanza
$ echo "city is ${city}"
city is pfungen-CH
#giacecco
To include a hiphen in the regex you could change the two lines as such in answer from #starfry.
Change these two lines:
local re1='^(\w+=\w+)&?'
local re2='^(\w+)=(\w+)$'
To these two lines:
local re1='^(\w+=(\w+|-|)+)&?'
local re2='^(\w+)=((\w+|-|)+)$'
For all those who couldn't get it working with the posted answers (like me),
this guy figured it out.
Can't upvote his post unfortunately...
Let me repost the code here real quick:
#!/bin/sh
if [ "$REQUEST_METHOD" = "POST" ]; then
if [ "$CONTENT_LENGTH" -gt 0 ]; then
read -n $CONTENT_LENGTH POST_DATA <&0
fi
fi
#echo "$POST_DATA" > data.bin
IFS='=&'
set -- $POST_DATA
#2- Value1
#4- Value2
#6- Value3
#8- Value4
echo $2 $4 $6 $8
echo "Content-type: text/html"
echo ""
echo "<html><head><title>Saved</title></head><body>"
echo "Data received: $POST_DATA"
echo "</body></html>"
Hope this is of help for anybody.
Cheers
Actually I liked bolt's answer, so I made a version which works with Busybox as well (ash in Busybox does not support here string).
This code will accept key1 and key2 parameters, all others will be ignored.
while IFS= read -r -d '&' KEYVAL && [[ -n "$KEYVAL" ]]; do
case ${KEYVAL%=*} in
key1) KEY1=${KEYVAL#*=} ;;
key2) KEY2=${KEYVAL#*=} ;;
esac
done <<END
$(echo "${QUERY_STRING}&")
END
One can use the bash-cgi.sh, which processes :
the query string into the $QUERY_STRING_GET key and value array;
the post request data (x-www-form-urlencoded) into the $QUERY_STRING_POST key and value array;
the cookies data into the $HTTP_COOKIES key and value array.
Demands bash version 4.0 or higher (to define the key and value arrays above).
All processing is made by bash only (i.e. in an one process) without any external dependencies and additional processes invoking.
It has:
the check for max length of data, which can be transferred to it's input,
as well as processed as query string and cookies;
the redirect() procedure to produce redirect to itself with the extension changed to .html (it is useful for an one page's sites);
the http_header_tail() procedure to output the last two strings of the HTTP(S) respond's header;
the $REMOTE_ADDR value sanitizer from possible injections;
the parser and evaluator of the escaped UTF-8 symbols embedded into the values passed to the $QUERY_STRING_GET, $QUERY_STRING_POST and $HTTP_COOKIES;
the sanitizer of the $QUERY_STRING_GET, $QUERY_STRING_POST and $HTTP_COOKIES values against possible SQL injections (the escaping like the mysql_real_escape_string php function does, plus the escaping of # and $).
It is available here:
https://github.com/VladimirBelousov/fancy_scripts
This works in dash using for in loop
IFS='&'
for f in $query_string; do
value=${f##*=}
key=${f%%=*}
# if you need environment variable -> eval "qs_$key=$value"
done