Please forgive a bash newbie for any silly questions.
I am really stuck here and I would love to know how this works and what I am doing wrong.
I have written this script which is supposed to capture syslog server based on protocol.
The input is as follows:
sys syslog {
include "destination remote_server {tcp(\"10.1.0.100\" port (514));tcp(\"192.168.1.5\" port (514));udp(\"192.168.1.60\" port (514));};filter f_alllogs {level (debug...emerg);};log {source(local);filter(f_alllogs);destination(remote_server);};"
remote-servers {
mysyslog {
host 192.168.1.1
}
remotesyslog1 {
host 192.168.1.2
}
remotesyslog2 {
host 192.168.1.3
local-ip 10.0.0.50
}
}
}
From this I would like to get something like in the end:
tcp=10.1.0.100
tcp=192.168.1.50
udp=192.168.1.60
udp=192.168.1.1
udp=192.168.1.2
udp=192.168.1.3
So I started with a bash script to parse the output.
#!/bin/bash
#Save output to file
syslogoutput=$(< /home/patrik/input)
echo "Testing variable:"
echo $syslogoutput
echo ""
#Declare array
tcpservers=()
echo $syslogoutput | while read line ; do
matches=($(echo $line | grep -Po '(tcp\("[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}")'))
#If number of matches is greater than 0, save them to tcpservers
if [ ${#matches[#]} -gt 0 ]; then
tcpservers=("${matches[#]}")
#Echoing matches
echo "Testing matches in loop:"
for i in "${matches[#]}"; do
echo $i
done
fi
done
echo "Testing output:"
for i in "${tcpservers[#]}"; do
echo $i
done
I expected something like this:
...input file separated by line breaks
Testing matches in loop:
tcp("10.1.0.100"
tcp("192.168.1.5"
Testing output:
tcp("10.1.0.100"
tcp("192.168.1.5"
But instead I get:
sys syslog { include "destination remote_server {tcp(\"10.1.0.100\" port (514));tcp(\"192.168.1.5\" port (514));udp(\"192.168.1.60\" port (514));};filter f_alllogs {level (debug...emerg);};log {source(local);filter(f_alllogs);destination(remote_server);};" remote-servers { mysyslog { host 192.168.1.1 } remotesyslog1 { host 192.168.1.2 } remotesyslog2 { host 192.168.1.3 local-ip 10.0.0.50 } } }
Testing matches in loop:
tcp("10.1.0.100"
tcp("192.168.1.5"
Testing output:
So on to my questions:
Why isn't tcpservers=("${matches[#]}") working?
Why isn't the output cached with line breaks?
Why does bash scripting make me want to jump from a tall building every time I try it?
/Patrik
Don't use redirection, as it starts the loop in a subshell, and variables form a subshell don't propagate into the parent shell.
while read line ; do
# ...
done <<< "$syslogoutput"
You also overwrite the tcpservers on each iteration. Change the assignment to
tcpservers+=("${matches[#]}")
# ^
# |
# add to an array, don't overwrite
Related
In the following program, if I set the variable $foo to the value 1 inside the first if statement, it works in the sense that its value is remembered after the if statement. However, when I set the same variable to the value 2 inside an if which is inside a while statement, it's forgotten after the while loop. It's behaving like I'm using some sort of copy of the variable $foo inside the while loop and I am modifying only that particular copy. Here's a complete test program:
#!/bin/bash
set -e
set -u
foo=0
bar="hello"
if [[ "$bar" == "hello" ]]
then
foo=1
echo "Setting \$foo to 1: $foo"
fi
echo "Variable \$foo after if statement: $foo"
lines="first line\nsecond line\nthird line"
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo "Value of \$foo in while loop body: $foo"
done
echo "Variable \$foo after while loop: $foo"
# Output:
# $ ./testbash.sh
# Setting $foo to 1: 1
# Variable $foo after if statement: 1
# Value of $foo in while loop body: 1
# Variable $foo updated to 2 inside if inside while loop
# Value of $foo in while loop body: 2
# Value of $foo in while loop body: 2
# Variable $foo after while loop: 1
# bash --version
# GNU bash, version 4.1.10(4)-release (i686-pc-cygwin)
echo -e $lines | while read line
...
done
The while loop is executed in a subshell. So any changes you do to the variable will not be available once the subshell exits.
Instead you can use a here string to re-write the while loop to be in the main shell process; only echo -e $lines will run in a subshell:
while read line
do
if [[ "$line" == "second line" ]]
then
foo=2
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo "Value of \$foo in while loop body: $foo"
done <<< "$(echo -e "$lines")"
You can get rid of the rather ugly echo in the here-string above by expanding the backslash sequences immediately when assigning lines. The $'...' form of quoting can be used there:
lines=$'first line\nsecond line\nthird line'
while read line; do
...
done <<< "$lines"
UPDATED#2
Explanation is in Blue Moons's answer.
Alternative solutions:
Eliminate echo
while read line; do
...
done <<EOT
first line
second line
third line
EOT
Add the echo inside the here-is-the-document
while read line; do
...
done <<EOT
$(echo -e $lines)
EOT
Run echo in background:
coproc echo -e $lines
while read -u ${COPROC[0]} line; do
...
done
Redirect to a file handle explicitly (Mind the space in < <!):
exec 3< <(echo -e $lines)
while read -u 3 line; do
...
done
Or just redirect to the stdin:
while read line; do
...
done < <(echo -e $lines)
And one for chepner (eliminating echo):
arr=("first line" "second line" "third line");
for((i=0;i<${#arr[*]};++i)) { line=${arr[i]};
...
}
Variable $lines can be converted to an array without starting a new sub-shell. The characters \ and n has to be converted to some character (e.g. a real new line character) and use the IFS (Internal Field Separator) variable to split the string into array elements. This can be done like:
lines="first line\nsecond line\nthird line"
echo "$lines"
OIFS="$IFS"
IFS=$'\n' arr=(${lines//\\n/$'\n'}) # Conversion
IFS="$OIFS"
echo "${arr[#]}", Length: ${#arr[*]}
set|grep ^arr
Result is
first line\nsecond line\nthird line
first line second line third line, Length: 3
arr=([0]="first line" [1]="second line" [2]="third line")
You are asking this bash FAQ. The answer also describes the general case of variables set in subshells created by pipes:
E4) If I pipe the output of a command into read variable, why
doesn't the output show up in $variable when the read command finishes?
This has to do with the parent-child relationship between Unix
processes. It affects all commands run in pipelines, not just
simple calls to read. For example, piping a command's output
into a while loop that repeatedly calls read will result in
the same behavior.
Each element of a pipeline, even a builtin or shell function,
runs in a separate process, a child of the shell running the
pipeline. A subprocess cannot affect its parent's environment.
When the read command sets the variable to the input, that
variable is set only in the subshell, not the parent shell. When
the subshell exits, the value of the variable is lost.
Many pipelines that end with read variable can be converted
into command substitutions, which will capture the output of
a specified command. The output can then be assigned to a
variable:
grep ^gnu /usr/lib/news/active | wc -l | read ngroup
can be converted into
ngroup=$(grep ^gnu /usr/lib/news/active | wc -l)
This does not, unfortunately, work to split the text among
multiple variables, as read does when given multiple variable
arguments. If you need to do this, you can either use the
command substitution above to read the output into a variable
and chop up the variable using the bash pattern removal
expansion operators or use some variant of the following
approach.
Say /usr/local/bin/ipaddr is the following shell script:
#! /bin/sh
host `hostname` | awk '/address/ {print $NF}'
Instead of using
/usr/local/bin/ipaddr | read A B C D
to break the local machine's IP address into separate octets, use
OIFS="$IFS"
IFS=.
set -- $(/usr/local/bin/ipaddr)
IFS="$OIFS"
A="$1" B="$2" C="$3" D="$4"
Beware, however, that this will change the shell's positional
parameters. If you need them, you should save them before doing
this.
This is the general approach -- in most cases you will not need to
set $IFS to a different value.
Some other user-supplied alternatives include:
read A B C D << HERE
$(IFS=.; echo $(/usr/local/bin/ipaddr))
HERE
and, where process substitution is available,
read A B C D < <(IFS=.; echo $(/usr/local/bin/ipaddr))
Hmmm... I would almost swear that this worked for the original Bourne shell, but don't have access to a running copy just now to check.
There is, however, a very trivial workaround to the problem.
Change the first line of the script from:
#!/bin/bash
to
#!/bin/ksh
Et voila! A read at the end of a pipeline works just fine, assuming you have the Korn shell installed.
This is an interesting question and touches on a very basic concept in Bourne shell and subshell. Here I provide a solution that is different from the previous solutions by doing some kind of filtering. I will give an example that may be useful in real life. This is a fragment for checking that downloaded files conform to a known checksum. The checksum file look like the following (Showing just 3 lines):
49174 36326 dna_align_feature.txt.gz
54757 1 dna.txt.gz
55409 9971 exon_transcript.txt.gz
The shell script:
#!/bin/sh
.....
failcnt=0 # this variable is only valid in the parent shell
#variable xx captures all the outputs from the while loop
xx=$(cat ${checkfile} | while read -r line; do
num1=$(echo $line | awk '{print $1}')
num2=$(echo $line | awk '{print $2}')
fname=$(echo $line | awk '{print $3}')
if [ -f "$fname" ]; then
res=$(sum $fname)
filegood=$(sum $fname | awk -v na=$num1 -v nb=$num2 -v fn=$fname '{ if (na == $1 && nb == $2) { print "TRUE"; } else { print "FALSE"; }}')
if [ "$filegood" = "FALSE" ]; then
failcnt=$(expr $failcnt + 1) # only in subshell
echo "$fname BAD $failcnt"
fi
fi
done | tail -1) # I am only interested in the final result
# you can capture a whole bunch of texts and do further filtering
failcnt=${xx#* BAD } # I am only interested in the number
# this variable is in the parent shell
echo failcnt $failcnt
if [ $failcnt -gt 0 ]; then
echo $failcnt files failed
else
echo download successful
fi
The parent and subshell communicate through the echo command. You can pick some easy to parse text for the parent shell. This method does not break your normal way of thinking, just that you have to do some post processing. You can use grep, sed, awk, and more for doing so.
I use stderr to store within a loop, and read from it outside.
Here var i is initially set and read inside the loop as 1.
# reading lines of content from 2 files concatenated
# inside loop: write value of var i to stderr (before iteration)
# outside: read var i from stderr, has last iterative value
f=/tmp/file1
g=/tmp/file2
i=1
cat $f $g | \
while read -r s;
do
echo $s > /dev/null; # some work
echo $i > 2
let i++
done;
read -r i < 2
echo $i
Or use the heredoc method to reduce the amount of code in a subshell.
Note the iterative i value can be read outside the while loop.
i=1
while read -r s;
do
echo $s > /dev/null
let i++
done <<EOT
$(cat $f $g)
EOT
let i--
echo $i
How about a very simple method
+call your while loop in a function
- set your value inside (nonsense, but shows the example)
- return your value inside
+capture your value outside
+set outside
+display outside
#!/bin/bash
# set -e
# set -u
# No idea why you need this, not using here
foo=0
bar="hello"
if [[ "$bar" == "hello" ]]
then
foo=1
echo "Setting \$foo to $foo"
fi
echo "Variable \$foo after if statement: $foo"
lines="first line\nsecond line\nthird line"
function my_while_loop
{
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2; return 2;
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2;
echo "Variable \$foo updated to $foo inside if inside while loop"
return 2;
fi
# Code below won't be executed since we returned from function in 'if' statement
# We aready reported the $foo var beint set to 2 anyway
echo "Value of \$foo in while loop body: $foo"
done
}
my_while_loop; foo="$?"
echo "Variable \$foo after while loop: $foo"
Output:
Setting $foo 1
Variable $foo after if statement: 1
Value of $foo in while loop body: 1
Variable $foo after while loop: 2
bash --version
GNU bash, version 3.2.51(1)-release (x86_64-apple-darwin13)
Copyright (C) 2007 Free Software Foundation, Inc.
Though this is an old question and asked several times, here's what I'm doing after hours fidgeting with here strings, and the only option that worked for me is to store the value in a file during while loop sub-shells and then retrieve it. Simple.
Use echo statement to store and cat statement to retrieve. And the bash user must chown the directory or have read-write chmod access.
#write to file
echo "1" > foo.txt
while condition; do
if (condition); then
#write again to file
echo "2" > foo.txt
fi
done
#read from file
echo "Value of \$foo in while loop body: $(cat foo.txt)"
In the following program, if I set the variable $foo to the value 1 inside the first if statement, it works in the sense that its value is remembered after the if statement. However, when I set the same variable to the value 2 inside an if which is inside a while statement, it's forgotten after the while loop. It's behaving like I'm using some sort of copy of the variable $foo inside the while loop and I am modifying only that particular copy. Here's a complete test program:
#!/bin/bash
set -e
set -u
foo=0
bar="hello"
if [[ "$bar" == "hello" ]]
then
foo=1
echo "Setting \$foo to 1: $foo"
fi
echo "Variable \$foo after if statement: $foo"
lines="first line\nsecond line\nthird line"
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo "Value of \$foo in while loop body: $foo"
done
echo "Variable \$foo after while loop: $foo"
# Output:
# $ ./testbash.sh
# Setting $foo to 1: 1
# Variable $foo after if statement: 1
# Value of $foo in while loop body: 1
# Variable $foo updated to 2 inside if inside while loop
# Value of $foo in while loop body: 2
# Value of $foo in while loop body: 2
# Variable $foo after while loop: 1
# bash --version
# GNU bash, version 4.1.10(4)-release (i686-pc-cygwin)
echo -e $lines | while read line
...
done
The while loop is executed in a subshell. So any changes you do to the variable will not be available once the subshell exits.
Instead you can use a here string to re-write the while loop to be in the main shell process; only echo -e $lines will run in a subshell:
while read line
do
if [[ "$line" == "second line" ]]
then
foo=2
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo "Value of \$foo in while loop body: $foo"
done <<< "$(echo -e "$lines")"
You can get rid of the rather ugly echo in the here-string above by expanding the backslash sequences immediately when assigning lines. The $'...' form of quoting can be used there:
lines=$'first line\nsecond line\nthird line'
while read line; do
...
done <<< "$lines"
UPDATED#2
Explanation is in Blue Moons's answer.
Alternative solutions:
Eliminate echo
while read line; do
...
done <<EOT
first line
second line
third line
EOT
Add the echo inside the here-is-the-document
while read line; do
...
done <<EOT
$(echo -e $lines)
EOT
Run echo in background:
coproc echo -e $lines
while read -u ${COPROC[0]} line; do
...
done
Redirect to a file handle explicitly (Mind the space in < <!):
exec 3< <(echo -e $lines)
while read -u 3 line; do
...
done
Or just redirect to the stdin:
while read line; do
...
done < <(echo -e $lines)
And one for chepner (eliminating echo):
arr=("first line" "second line" "third line");
for((i=0;i<${#arr[*]};++i)) { line=${arr[i]};
...
}
Variable $lines can be converted to an array without starting a new sub-shell. The characters \ and n has to be converted to some character (e.g. a real new line character) and use the IFS (Internal Field Separator) variable to split the string into array elements. This can be done like:
lines="first line\nsecond line\nthird line"
echo "$lines"
OIFS="$IFS"
IFS=$'\n' arr=(${lines//\\n/$'\n'}) # Conversion
IFS="$OIFS"
echo "${arr[#]}", Length: ${#arr[*]}
set|grep ^arr
Result is
first line\nsecond line\nthird line
first line second line third line, Length: 3
arr=([0]="first line" [1]="second line" [2]="third line")
You are asking this bash FAQ. The answer also describes the general case of variables set in subshells created by pipes:
E4) If I pipe the output of a command into read variable, why
doesn't the output show up in $variable when the read command finishes?
This has to do with the parent-child relationship between Unix
processes. It affects all commands run in pipelines, not just
simple calls to read. For example, piping a command's output
into a while loop that repeatedly calls read will result in
the same behavior.
Each element of a pipeline, even a builtin or shell function,
runs in a separate process, a child of the shell running the
pipeline. A subprocess cannot affect its parent's environment.
When the read command sets the variable to the input, that
variable is set only in the subshell, not the parent shell. When
the subshell exits, the value of the variable is lost.
Many pipelines that end with read variable can be converted
into command substitutions, which will capture the output of
a specified command. The output can then be assigned to a
variable:
grep ^gnu /usr/lib/news/active | wc -l | read ngroup
can be converted into
ngroup=$(grep ^gnu /usr/lib/news/active | wc -l)
This does not, unfortunately, work to split the text among
multiple variables, as read does when given multiple variable
arguments. If you need to do this, you can either use the
command substitution above to read the output into a variable
and chop up the variable using the bash pattern removal
expansion operators or use some variant of the following
approach.
Say /usr/local/bin/ipaddr is the following shell script:
#! /bin/sh
host `hostname` | awk '/address/ {print $NF}'
Instead of using
/usr/local/bin/ipaddr | read A B C D
to break the local machine's IP address into separate octets, use
OIFS="$IFS"
IFS=.
set -- $(/usr/local/bin/ipaddr)
IFS="$OIFS"
A="$1" B="$2" C="$3" D="$4"
Beware, however, that this will change the shell's positional
parameters. If you need them, you should save them before doing
this.
This is the general approach -- in most cases you will not need to
set $IFS to a different value.
Some other user-supplied alternatives include:
read A B C D << HERE
$(IFS=.; echo $(/usr/local/bin/ipaddr))
HERE
and, where process substitution is available,
read A B C D < <(IFS=.; echo $(/usr/local/bin/ipaddr))
Hmmm... I would almost swear that this worked for the original Bourne shell, but don't have access to a running copy just now to check.
There is, however, a very trivial workaround to the problem.
Change the first line of the script from:
#!/bin/bash
to
#!/bin/ksh
Et voila! A read at the end of a pipeline works just fine, assuming you have the Korn shell installed.
This is an interesting question and touches on a very basic concept in Bourne shell and subshell. Here I provide a solution that is different from the previous solutions by doing some kind of filtering. I will give an example that may be useful in real life. This is a fragment for checking that downloaded files conform to a known checksum. The checksum file look like the following (Showing just 3 lines):
49174 36326 dna_align_feature.txt.gz
54757 1 dna.txt.gz
55409 9971 exon_transcript.txt.gz
The shell script:
#!/bin/sh
.....
failcnt=0 # this variable is only valid in the parent shell
#variable xx captures all the outputs from the while loop
xx=$(cat ${checkfile} | while read -r line; do
num1=$(echo $line | awk '{print $1}')
num2=$(echo $line | awk '{print $2}')
fname=$(echo $line | awk '{print $3}')
if [ -f "$fname" ]; then
res=$(sum $fname)
filegood=$(sum $fname | awk -v na=$num1 -v nb=$num2 -v fn=$fname '{ if (na == $1 && nb == $2) { print "TRUE"; } else { print "FALSE"; }}')
if [ "$filegood" = "FALSE" ]; then
failcnt=$(expr $failcnt + 1) # only in subshell
echo "$fname BAD $failcnt"
fi
fi
done | tail -1) # I am only interested in the final result
# you can capture a whole bunch of texts and do further filtering
failcnt=${xx#* BAD } # I am only interested in the number
# this variable is in the parent shell
echo failcnt $failcnt
if [ $failcnt -gt 0 ]; then
echo $failcnt files failed
else
echo download successful
fi
The parent and subshell communicate through the echo command. You can pick some easy to parse text for the parent shell. This method does not break your normal way of thinking, just that you have to do some post processing. You can use grep, sed, awk, and more for doing so.
I use stderr to store within a loop, and read from it outside.
Here var i is initially set and read inside the loop as 1.
# reading lines of content from 2 files concatenated
# inside loop: write value of var i to stderr (before iteration)
# outside: read var i from stderr, has last iterative value
f=/tmp/file1
g=/tmp/file2
i=1
cat $f $g | \
while read -r s;
do
echo $s > /dev/null; # some work
echo $i > 2
let i++
done;
read -r i < 2
echo $i
Or use the heredoc method to reduce the amount of code in a subshell.
Note the iterative i value can be read outside the while loop.
i=1
while read -r s;
do
echo $s > /dev/null
let i++
done <<EOT
$(cat $f $g)
EOT
let i--
echo $i
How about a very simple method
+call your while loop in a function
- set your value inside (nonsense, but shows the example)
- return your value inside
+capture your value outside
+set outside
+display outside
#!/bin/bash
# set -e
# set -u
# No idea why you need this, not using here
foo=0
bar="hello"
if [[ "$bar" == "hello" ]]
then
foo=1
echo "Setting \$foo to $foo"
fi
echo "Variable \$foo after if statement: $foo"
lines="first line\nsecond line\nthird line"
function my_while_loop
{
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2; return 2;
echo "Variable \$foo updated to $foo inside if inside while loop"
fi
echo -e $lines | while read line
do
if [[ "$line" == "second line" ]]
then
foo=2;
echo "Variable \$foo updated to $foo inside if inside while loop"
return 2;
fi
# Code below won't be executed since we returned from function in 'if' statement
# We aready reported the $foo var beint set to 2 anyway
echo "Value of \$foo in while loop body: $foo"
done
}
my_while_loop; foo="$?"
echo "Variable \$foo after while loop: $foo"
Output:
Setting $foo 1
Variable $foo after if statement: 1
Value of $foo in while loop body: 1
Variable $foo after while loop: 2
bash --version
GNU bash, version 3.2.51(1)-release (x86_64-apple-darwin13)
Copyright (C) 2007 Free Software Foundation, Inc.
Though this is an old question and asked several times, here's what I'm doing after hours fidgeting with here strings, and the only option that worked for me is to store the value in a file during while loop sub-shells and then retrieve it. Simple.
Use echo statement to store and cat statement to retrieve. And the bash user must chown the directory or have read-write chmod access.
#write to file
echo "1" > foo.txt
while condition; do
if (condition); then
#write again to file
echo "2" > foo.txt
fi
done
#read from file
echo "Value of \$foo in while loop body: $(cat foo.txt)"
I have a short bash script to check to see if a Python program is running. The program writes out a PID file when it runs, so comparing this to the current list of running processes gives me what I need. But I'm having a problem with a variable being changed and then apparently changing back! Here's the script:
#!/bin/bash
# Test whether Home Server is currently running
PIDFILE=/tmp/montSvr.pid
isRunning=0
# does a pid file exist?
if [ -f "$PIDFILE" ]; then
# pid file exists
# now get contents of pid file
cat $PIDFILE | while read PID; do
if [ $PID != "" ]; then
PSGREP=$(ps -A | grep $PID | awk '{print $1}')
if [ -n "$PSGREP" ]; then
isRunning=1
echo "RUNNING: $isRunning"
fi
fi
done
fi
echo "Running: $isRunning"
exit $isRunning
The output I get, when the Python script is running, is:
RUNNING: 1
Running: 0
And the exit value of the bash script is 0. So isRunning is getting changed within all those if statements (ie, the code is performing as expected), but then somehow isRunning reverts to 0 again. Confused...
Commands after a pipe | are run in a subshell. Changes to variable values in a subshell do not propagate to the parent shell.
Solution: change your loop to
while read PID; do
# ...
done < $PIDFILE
It's the pipe that is the problem. Using a pipe in this way means that the loop runs in a sub-shell, with its own environment. Kill the cat, use this syntax instead:
while read PID; do
if [ $PID != "" ]; then
PSGREP=$(ps -A | grep $PID | awk '{print $1}')
if [ -n "$PSGREP" ]; then
isRunning=1
echo "RUNNING: $isRunning"
fi
fi
done < "$PIDFILE"
i have a a files containing usernames and users sent count mail per line . for example (dont know how many line have ) :
info.txt >
500 example1
40 example2
20 example3
....
..
.
if the number was greater than X , i want to run commands containing the user name and act on user .
getArray() {
users=() # Create array
while IFS= read -r line # Read a line
do
users+=("$line") # Append line to the array
done < "$1"
}
getArray "/root/.myscripts/spam1/info.txt"
# i know this part is incorrect and need help here :
if [ "${users[1$]}" -gt "50" ]
then
echo "${users[2$] has sent ${users[1$]} emails"
fi
please Help
Thanks
Not knowing how many lines of input you have is no reason to use an array. Indeed, it is generally more useful if you assume your input is infinite (an input stream), so reading into an array is impossible. Just read each line and take action if necessary:
#!/bin/sh
while read -r count user; do
if test "$count" -gt 50; then
echo "$user has sent $count emails"
fi
done < /root/.myscripts/spam1/info.txt
I'm currently writing a shell script that reads a Vagrantfile and bootstraps it (in a nutshell ;) )
But I'm hitting a wall with the following piece of code:
TEST=()
while read result; do
TEST+=(`echo ${result}`)
done <<< `awk '/config.vm.define[ \s]\"[a-z]*\"[ \s]do[ \s]\|[a-zA-Z_]*\|/, /end/ { print }' Vagrantfile`
echo "${TEST[1]}"
When I pass a Vagrantfile into this awk pattern regex with two machines defined (config.vm.define) in it they are found.
The output
config.vm.define "web" do |web|
web.vm.box = "CentOs"
web.vm.box_url = "http://developer.nrel.gov/downloads/vagrant-boxes/CentOS-6.4-x86_64-v20130731.box"
web.vm.hostname = 'dev.local'
web.vm.network :forwarded_port, guest: 90, host: 9090
web.vm.network :private_network, ip: "22.22.22.11"
web.vm.provision :puppet do |puppet|
puppet.manifests_path = "puppet/manifests"
puppet.manifest_file = "web.pp"
puppet.module_path = "puppet/modules"
puppet.options = ["--verbose", "--hiera_config /vagrant/hiera.yaml", "--parser future"]
end
config.vm.define "db" do |db_mysql|
db_mysql.vm.box = "CentOs"
db_mysql.vm.box_url = "http://developer.nrel.gov/downloads/vagrant-boxes/CentOS-6.4-x86_64-v20130731.box"
db_mysql.vm.hostname = 'db.mysql.local'
db_mysql.vm.network :private_network, ip: "22.22.22.22"
db_mysql.vm.network :forwarded_port, guest: 3306, host: 3306
db_mysql.vm.provision :puppet do |puppet|
puppet.manifests_path = "puppet/manifests"
puppet.manifest_file = "db.pp"
puppet.module_path = "puppet/modules"
puppet.options = ["--verbose", "--hiera_config /vagrant/hiera.yaml", "--parser future"]
end
But I can't seem to pass them into a array nicely. What I want is that the TEST array contains two indexes with the machine config.vm.define block as their corresponding values.
E.g.
TEST[0] = 'config.vm.define "web" do |web|
.... [REST OF THE BLOCK CONTENT] ...
end'
TEST[1] = 'config.vm.define "db" do |db_mysql|
.... [REST OF THE BLOCK CONTENT] ...
end'
The output echo "${TEST[1]}" is nothing. echo "${TEST[0]}" returns the whole block as plotted above.
I played with IFS / RS / FS but I can't seem to get the output I want.
A solution might be to write the two blocks to two separate files (blk1 and blk2) as:
awk '
/config.vm.define[[:space:]]\"[a-z]*\"[[:space:]]do[[:space:]]\|[a-zA-Z_]*\|/{f=1; i++}
f{print $0 > "blk"i}
/end/ {f=0}' Vagrantfile
and then later read these two files into the bash array as
IFS= TEST=( $(cat <"blk1") $(cat <"blk2") )
Note:
The regex \s seems to work only for the latest version of gawk (Works with version 4.1, but not version 3.1.8.
For gawk version 3.1.8, use [[:space:]] instead.
For gawk version 4.1, the regex \s does not work inside brackets [\s]. Use either config.vm.define[[:space:]] or config.vm.define\s..
Update
An alternative could be to insert an artificial separator between the blocks, for instance the string ###. Then you could do
IFS= TEST=()
while IFS= read -r -d '#' line ; do
TEST+=($line)
done < <(awk '
/config.vm.define[[:space:]]\"[a-z]*\"[[:space:]]do[[:space:]]\|[a-zA-Z_]*\|/{f=1; i++}
f{print }
/end/ {f=0; print "###"}' Vagrantfile)