How can I make an array from a link?
I am trying to do it with:
IFS=$'\n'
array=($(curl http://www.site.com))
but I keep getting a syntax error
You have:
array=(($curl http://www.site.com))
^^
Move the $ slightly:
$ array=($(curl http://www.example.com))
^
$ echo ${array[3]}
<title>Example Domain</title>
You are using BASH arrays here. A common issue is that you're shebang is still pointing to the POSIX sh. The old POSIX sh doesn't support arrays. Make sure the top line of your file looks like this:
#!/bin/bash
Related
I'm not sure if this has been answered, I've looked and haven't found anything that looks like what I'm trying to do. I also posted this to stackexchange (https://unix.stackexchange.com/questions/189293/create-array-in-bash-with-variables-as-array-name)
I have a number of shell scripts that are capable of running against a ksh or bash shell, and they make use of arrays. I created a function named "setArray" that interrogates the running shell and determines what builtin to use to create the array - for ksh, set -A, for bash, typeset -a. However, I'm having some issues with the bash portion.
The function takes two arguments, the name of the array and the value to add. This then becomes ${ARRAY_NAME} and ${VARIABLE_VALUE}. Doing the following:
set -A $(eval echo \${ARRAY_NAME}) $(eval echo \${${ARRAY_NAME}[*]}) "${VARIABLE_VALUE}"
works perfectly in ksh. However,
typeset -a $(eval echo \${ARRAY_NAME})=( $(eval echo \${${ARRAY_NAME}[*]}) "${VARIABLE_VALUE}" )
does not. This provides
bash: syntax error near unexpected token '('
I know I can just make it a list of strings (e.g. MYARRAY="one two three") and just loop through it using the IFS, but I don't want to lose the ability to use an array either.
Any thoughts ?
Given the assertion that the ksh portion of this function is working only the bash portion needs to be created. For which the following should work and, I believe, be safe and robust (though evidence to the contrary is welcome).
eval $ARRAY_NAME+=\(\"\$VARIABLE_VALUE\"\)
First expansion only expands $ARRAY_NAME to get
eval array+=("$VARIABLE_VALUE")
which eval then causes to be evaluated again normally.
I'm trying to create a loop for a couple of arrays but I get this error:
./bash.sh: 3: ./bash.sh: source[0]=/media/jon/my\ directory/: not found
This is what my code looks like:
sourceFiles[1]=/media/jon/ACER/Documents\ and\ Settings/Laura/Documents/Shared
destinationFiles[1]=/media/jon/My\ Book/Shared
for index in ${!sourceFiles[#]}
do
sudo rsync -a --delete ${sourceFiles[$index]} ${destinationFiles[$index]}
done
I'm some what green to bash files and this is terribly frustrating that doing a simple loop is so difficult.
Update
I needed a #!/bin/bash at the top per the correct answer.
Your code looks ok. I think you're not using bash though ("not found" is not a bash error message). Are you perhaps using /bin/sh? On many systems that's a minimal POSIX shell, not bash.
A POSIX shell would not recognize sourceFiles[1]=... as an assignment and would consequently run it as a command. Hence the "not found" error.
Try enclosing in double quote your variables in your sudo line:
sudo rsync -a --delete "${sourceFiles[$index]}" "${destinationFiles[$index]}"
How can I run a command line from a bash array containing a pipeline?
For example, I want run ls | grep x by means of:
$ declare -a pipeline
$ pipeline=(ls)
$ pipeline+=("|")
$ pipeline+=(grep x)
$ "${pipeline[#]}"
But I get this:
ls: cannot access |: No such file or directory
ls: cannot access grep: No such file or directory
ls: cannot access x: No such file or directory
Short form: You can't (without writing some code), and it's a feature, not a bug.
If you're doing things in a safe way, you're protecting your data from being parsed as code (syntax). What you explicitly want here, however, is to treat data as code, but only in a controlled way.
What you can do is iterate over elements, use printf '%q ' "$element" to get a safely quoted string if they aren't a pipeline, and leave them unsubstituted if they are.
After doing that, and ONLY after doing that, can you safely eval the output string.
eval_args() {
local outstr=''
while (( $# )); do
if [[ $1 = '|' ]]; then
outstr+="| "
else
printf -v outstr '%s%q ' "$outstr" "$1"
fi
shift
done
eval "$outstr"
}
eval_args "${pipeline[#]}"
By the way -- it's much safer NOT TO DO THIS. Think about the case where you're processing a list of files, and one of them is named |; this strategy could be used by an attacker to inject code. Using separate lists for the before and after arrays, or making only one side of the pipeline an array and hardcoding the other, is far better practice.
Close - just add eval:
$ eval ${pipeline[#]}
This works for me:
bash -c "${pipeline[*]}"
The below code is is not working as I expect it to. I might be because I am doing this all wrong but I think it may be a quoting issue.
#!/bin/bash
IFS=$'\n'
fortune_lines=($(fortune | fold -w 30))
Screen_Session=$(mainscreen)
Screen_OneLiner=$(screen -p 0 -S ${Screen_Session} -X stuff "`printf "say ${fortune_lines[#]}\r"`")
for var in "${Screen_OneLiner[#]}"
do
echo "${var}"
done
I think I am not quoting something correctly because when I attempt to execute this. I get..
line 5: mainscreen: command not found
[screen is terminating
Essentially I am attempting to add this function (that works)
IFS=$'\n'
fortune_lines=($(fortune | fold -w 30))
To this screen one liner
screen -p 0 -S ${Screen_Session} -X stuff "`printf "say ${fortune_lines[#]}\r"`"
Then have it loop the array
for var in "${ArrayName[#]}"
do
echo "${var}"
done
So I am not sure how far I am away (in code) to what I am trying to do. Any help would be great.
Since feature requests to mark a comment as an answer remain declined, I copy the above solution here.
I managed to get this to work... gist.github.com/4006586 – user1787331
This line is problematic
Screen_Session=$(mainscreen)
You are using command substitution here, so if mainscreen is not a valid command, you'll get command not found error.
Maybe you mean to use braces instead of parentheses?
I have some bash script where I get values of variable, that I would like use in awk.
Does it possible include whole awk (like it possible with bash script files) file in bash e.g.:
#!/bin/sh
var1=$1
source myawk.sh
and myawk.sh:
print $1;
Bash and awk are different languages, each with their own interpreter of the same name. The tiny sample you show is stripped down too far to make much sense:
You've marked both files as shell scripts; one using the shebang #!/bin/sh and the other using the extension .sh. Obviously the shell can read shell script, and the command to do so is called . in Bourne shell (or source in csh and bash).
The shell script assigns a variable, but you're not using it anywhere. Did you mean passing it on to the awk script?
Both the awk and shell script use $1, which has different meanings for them (in bash, it's from the command line or a set command; in awk, it's from a parsed input line).
The two tools are often used in tandem, as the shell is better at combining separate programs and awk is better at reformatting tabular or structured text. It was so common that a whole language evolved to combine the tasks; Perl's roots are as a combination of shell, awk and sed.
If you just wanted to pass a variable from the shell script into an awk script, use -v. The man page is your friend.
first of all, if you're writing bash don't use #!/bin/sh that will put you in compatibility mode which is only necessarly if you're writing for portability (and then you have to adhere to the POSIX normative).
now regarding your question you just have to run awk from inside your bash script, like this:
#!/bin/bash
var1=$1
awk -f myawk.sh
also you should use .awk as extension I guess.
Or, many ppl do sth like this:
#!/bin/env bash
#Bash things start
...
var1=$1
#Bash things stop
#Awk things start,
#may use pipes or variable to interact with bash
awk -v V1=var1 '
#AWK program, can even include awk scripts here.
'
#Bash things
I suggest this page here by Bruce Barnett:
http://www.grymoire.com/Unix/Awk.html#uh-3
You can also use double quote to make use of shell's extract feature but it is confusing.
Personally I just try to avoid those fancy gnu additions of bash or awk and make my scripts ksh+(n)awk compatible.
As an hardcore AWK user, I soon realized that doing the following was really a huge help :
Defining and exporting an AWK_REPO variable in my bashrc
#Content of bashrc
export AWK_REPO=~/bin/AWK
Storing there every AWK script I write using the .awk extension.
You can then call it from anywhere like this :
awk -f $AWK_REPO/myScript.awk $file
or even, using Shebangs and adding AWK_REPO to PATH (with export PATH=${AWK_REPO}:${PATH})
myScript.awk $file