Fileread.sh
#!/bin/bash
s=ch.qos.logback
e=logback-access
curl -s "https://search.maven.org/solrsearch/select?q=g:$s+AND+a:$e&core=gav&rows=1&wt=json" | jq ".response.docs[].v"`
output:"1.2.11"
This code is working perfectly fine But when I try storing the s and e values in a .txt file with : seperated and then try running, I get nothing in response
textFile.txt
ch.qos.logback:logback-access
fileread.sh
#!/bin/bash
read -p "Enter file name:" filename
while IFS=':' read -r s e
do
curl -s "https://search.maven.org/solrsearch/select?q=g:${s}+AND+a:${e}&core=gav&rows=1&wt=json" | jq ".response.docs[].v"
done < $filename
I have tried :
xy=$(curl -s "https://search.maven.org/solrsearch/select?q=g:${s}+AND+a:${e}&core=gav&rows=1&wt=json" | jq ".response.docs[].v")
echo "$xy"
xy=$(curl -s "'https://search.maven.org/solrsearch/select?q=g:'${s}'+AND+a:'${e}&core=gav&rows=1&wt=json" | jq ".response.docs[].v")
echo "$xy"
url=`https://search.maven.org/solrsearch/select?q=g:${s}+AND+a:${e}&core=gav&rows=1&wt=json`
echo url
xx=`curl -s "$url" | jq ".response.docs[].v"`
echo $xx
Try this:
#!/bin/bash
echo "Enter file name:"
read filename
IFS=':' read -r s e < $filename
echo $s $e
curl -s "https://search.maven.org/solrsearch/select?q=g:${s}+AND+a:${e}&core=gav&rows=1&wt=json" | jq ".response.docs[].v"
~
I found some ways to pass external shell variables to an awk script, but I'm confused about ' and ".
First, I tried with a shell script:
$ v=123test
$ echo $v
123test
$ echo "$v"
123test
Then tried awk:
$ awk 'BEGIN{print "'$v'"}'
$ 123test
$ awk 'BEGIN{print '"$v"'}'
$ 123
Why is the difference?
Lastly I tried this:
$ awk 'BEGIN{print " '$v' "}'
$ 123test
$ awk 'BEGIN{print ' "$v" '}'
awk: cmd. line:1: BEGIN{print
awk: cmd. line:1: ^ unexpected newline or end of string
I'm confused about this.
#Getting shell variables into awk
may be done in several ways. Some are better than others. This should cover most of them. If you have a comment, please leave below. v1.5
Using -v (The best way, most portable)
Use the -v option: (P.S. use a space after -v or it will be less portable. E.g., awk -v var= not awk -vvar=)
variable="line one\nline two"
awk -v var="$variable" 'BEGIN {print var}'
line one
line two
This should be compatible with most awk, and the variable is available in the BEGIN block as well:
If you have multiple variables:
awk -v a="$var1" -v b="$var2" 'BEGIN {print a,b}'
Warning. As Ed Morton writes, escape sequences will be interpreted so \t becomes a real tab and not \t if that is what you search for. Can be solved by using ENVIRON[] or access it via ARGV[]
PS If you have vertical bar or other regexp meta characters as separator like |?( etc, they must be double escaped. Example 3 vertical bars ||| becomes -F'\\|\\|\\|'. You can also use -F"[|][|][|]".
Example on getting data from a program/function inn to awk (here date is used)
awk -v time="$(date +"%F %H:%M" -d '-1 minute')" 'BEGIN {print time}'
Example of testing the contents of a shell variable as a regexp:
awk -v var="$variable" '$0 ~ var{print "found it"}'
Variable after code block
Here we get the variable after the awk code. This will work fine as long as you do not need the variable in the BEGIN block:
variable="line one\nline two"
echo "input data" | awk '{print var}' var="${variable}"
or
awk '{print var}' var="${variable}" file
Adding multiple variables:
awk '{print a,b,$0}' a="$var1" b="$var2" file
In this way we can also set different Field Separator FS for each file.
awk 'some code' FS=',' file1.txt FS=';' file2.ext
Variable after the code block will not work for the BEGIN block:
echo "input data" | awk 'BEGIN {print var}' var="${variable}"
Here-string
Variable can also be added to awk using a here-string from shells that support them (including Bash):
awk '{print $0}' <<< "$variable"
test
This is the same as:
printf '%s' "$variable" | awk '{print $0}'
P.S. this treats the variable as a file input.
ENVIRON input
As TrueY writes, you can use the ENVIRON to print Environment Variables.
Setting a variable before running AWK, you can print it out like this:
X=MyVar
awk 'BEGIN{print ENVIRON["X"],ENVIRON["SHELL"]}'
MyVar /bin/bash
ARGV input
As Steven Penny writes, you can use ARGV to get the data into awk:
v="my data"
awk 'BEGIN {print ARGV[1]}' "$v"
my data
To get the data into the code itself, not just the BEGIN:
v="my data"
echo "test" | awk 'BEGIN{var=ARGV[1];ARGV[1]=""} {print var, $0}' "$v"
my data test
Variable within the code: USE WITH CAUTION
You can use a variable within the awk code, but it's messy and hard to read, and as Charles Duffy points out, this version may also be a victim of code injection. If someone adds bad stuff to the variable, it will be executed as part of the awk code.
This works by extracting the variable within the code, so it becomes a part of it.
If you want to make an awk that changes dynamically with use of variables, you can do it this way, but DO NOT use it for normal variables.
variable="line one\nline two"
awk 'BEGIN {print "'"$variable"'"}'
line one
line two
Here is an example of code injection:
variable='line one\nline two" ; for (i=1;i<=1000;++i) print i"'
awk 'BEGIN {print "'"$variable"'"}'
line one
line two
1
2
3
.
.
1000
You can add lots of commands to awk this way. Even make it crash with non valid commands.
One valid use of this approach, though, is when you want to pass a symbol to awk to be applied to some input, e.g. a simple calculator:
$ calc() { awk -v x="$1" -v z="$3" 'BEGIN{ print x '"$2"' z }'; }
$ calc 2.7 '+' 3.4
6.1
$ calc 2.7 '*' 3.4
9.18
There is no way to do that using an awk variable populated with the value of a shell variable, you NEED the shell variable to expand to become part of the text of the awk script before awk interprets it. (see comment below by Ed M.)
Extra info:
Use of double quote
It's always good to double quote variable "$variable"
If not, multiple lines will be added as a long single line.
Example:
var="Line one
This is line two"
echo $var
Line one This is line two
echo "$var"
Line one
This is line two
Other errors you can get without double quote:
variable="line one\nline two"
awk -v var=$variable 'BEGIN {print var}'
awk: cmd. line:1: one\nline
awk: cmd. line:1: ^ backslash not last character on line
awk: cmd. line:1: one\nline
awk: cmd. line:1: ^ syntax error
And with single quote, it does not expand the value of the variable:
awk -v var='$variable' 'BEGIN {print var}'
$variable
More info about AWK and variables
Read this faq.
It seems that the good-old ENVIRON awk built-in hash is not mentioned at all. An example of its usage:
$ X=Solaris awk 'BEGIN{print ENVIRON["X"], ENVIRON["TERM"]}'
Solaris rxvt
You could pass in the command-line option -v with a variable name (v) and a value (=) of the environment variable ("${v}"):
% awk -vv="${v}" 'BEGIN { print v }'
123test
Or to make it clearer (with far fewer vs):
% environment_variable=123test
% awk -vawk_variable="${environment_variable}" 'BEGIN { print awk_variable }'
123test
You can utilize ARGV:
v=123test
awk 'BEGIN {print ARGV[1]}' "$v"
Note that if you are going to continue into the body, you will need to adjust
ARGC:
awk 'BEGIN {ARGC--} {print ARGV[2], $0}' file "$v"
I just changed #Jotne's answer for "for loop".
for i in `seq 11 20`; do host myserver-$i | awk -v i="$i" '{print "myserver-"i" " $4}'; done
I had to insert date at the beginning of the lines of a log file and it's done like below:
DATE=$(date +"%Y-%m-%d")
awk '{ print "'"$DATE"'", $0; }' /path_to_log_file/log_file.log
It can be redirect to another file to save
Pro Tip
It could come handy to create a function that handles this so you dont have to type everything every time. Using the selected solution we get...
awk_switch_columns() {
cat < /dev/stdin | awk -v a="$1" -v b="$2" " { t = \$a; \$a = \$b; \$b = t; print; } "
}
And use it as...
echo 'a b c d' | awk_switch_columns 2 4
Output:
a d c b
I have a very simple bash script. I want to output the result of running the script to the html. However, html, "$ {ec_1} $ {ec_2}" was so.
#!/bin/bash
cat << 'EOF' > 01.html
<html>
<head>
<title>HTML Convert</title>
</head>
<body>
EOF
ec_1="====Default ID===="
if [ `cat /etc/passwd | egrep "lp:|uucp:|nuccp:" | wc -l` -eq 0 ] ; then
echo /etc/passwd | egrep "lp:|uucp:|nuccp:" > $ec_2
fi
cat << 'EOF' >> 01.html
<h1>${ec_1}</h1>
<h5>${ec_2}</h5>
</body>
</html>
EOF
[result 01.html]
${ec_1}
${ec_2}
Some notes (to large for an comment)
Your code:
if [ `cat /etc/passwd | egrep "lp:|uucp:|nuccp:" | wc -l` -eq 0 ] ; then
echo /etc/passwd | egrep "lp:|uucp:|nuccp:" > $ec_2
fi
Here you proof the number of output lines of egrep. If it produce no lines, you extract these 0 lines. I think, you mean -gt 0.
Then you wrote echo /etc/passwd. I think, cat /etc/passwd is correct, or egrep ... /etc/passwd.
Anyway, the if-condition is not necessary at all, just do:
egrep "lp:|uucp:|nuccp:" /etc/password > $ec_2
Otherwise, $ec_2 is undefined (no alternative if if ... is false.
>$ec_2 writes a file, and not a variable. Later you access undefined variable $ec_2.
I would like the simplest solution for my pretty basic bash script:
#!/bin/bash
# Weather API url format: http://api.wunderground.com/api/{api_key}/conditions/q/CA/{location}.json
# http://api.wunderground.com/api/5e8747237f05d669/conditions/q/CA/tbilisi.json
api_key=5e8747237f05d669
location=tbilisi
temp=c
api=$(wget -qO- http://api.wunderground.com/api/$api_key/conditions/q/CA/$location.json)
temp_c=$api | grep temp_c
temp_f=$api | grep temp_f
if [ $temp = "f" ]; then
echo $temp_f
else
echo $temp_c
fi
grep returns empty. This is my first bash script, I'm getting hold of syntax, so please point out obvious errors.
I also don't understand why I have $() for wget.
You can use:
temp_c=$(echo $api|awk '{print $2}' FS='temp_c":'|awk '{print $1}' FS=',')
temp_f=$(echo $api|awk '{print $2}' FS='temp_f":'|awk '{print $1}' FS=',')
Instead of:
temp_c=$api | grep temp_c
temp_f=$api | grep temp_f
I am getting following JSON response from curl and storing in variable :
CURL_OUTPUT='{ "url": "protocol://xyz.net/9999" , "other_key": "other_value" }'
Question :I want to read the url key value and extract the id from that url:
Answer : _ID=$(echo $CURL_OUTPUT |awk '{print $2}' FS='url":' |awk '{print $1}' FS=',' | awk '{print $2}' FS='"'|awk '{print $4}' FS='/')
I am having issues creating a html table to display stats from a text file. I am sure there are 100 ways to do this better but here it is:
(The comments in the following script show the outputs)
#!/bin/bash
function getapistats () {
curl -s http://api.example.com/stats > api-stats.txt
awk {'print $1'} api-stats.txt > api-stats-int.txt
awk {'print $2'} api-stats.txt > api-stats-fqdm.txt
}
# api-stats.txt example
# 992 cdn.example.com
# 227 static.foo.com
# 225 imgcdn.bar.com
# end api-stats.txt example
function get_int () {
for i in `cat api-stats-int.txt`;
do echo -e "<tr><td>${i}</td>";
done
}
function get_fqdn () {
for f in `cat api-stats-fqdn.txt`;
do echo -e "<td>${f}</td></tr>";
done
}
function build_table () {
echo "<table>";
echo -e "`get_int`" "`get_fqdn`";
#echo -e "`get_fqdn`";
echo "</table>";
}
getapistats;
build_table > api-stats.html;
# Output fail :|
# <table>
# <tr><td>992</td>
# <tr><td>227</td>
# <tr><td>225</td><td>cdn.example.com</td></tr>
# <td>static.foo.com</td></tr>
# <td>imgcdn.bar.com</td></tr>
# Desired output:
# <tr><td>992</td><td>cdn.example.com</td></tr>
# ...
This is reasonably simple to do in pure awk:
curl -s http://api.example.com/stats > api-stats.txt
awk 'BEGIN { print "<table>" }
{ print "<tr><td>" $1 "</td><td>" $2 "</td></tr>" }
END { print "</table>" }' api-stats.txt > api-stats.html
Awk is really made for this type of use.
You can do it with one awk at least.
curl -s http://api.example.com/stats | awk '
BEGIN{print "<table>"}
{printf("<tr><td>%d</td><td>%s</td></tr>\n",$1,$2)}
END{print "</table>"}
'
this can be done w/ bash ;)
while read -u 3 a && read -u 4 b;do
echo $a$b;
done 3</etc/passwd 4</etc/services
but my experience is that usually it's a bad thing to do things like this in bash/awk/etc
the feature i used in the code is deeply burried in the bash manual page...
i would recommend to use some real language for this kind of data processing for example: (ruby or python) because they are more flexible/readable/maintainable