Execute Command as a String in Bash

How to execute a bash command stored as a string with quotes and asterisk

Have you tried:

eval $cmd

For the follow-on question of how to escape * since it has special meaning when it's naked or in double quoted strings: use single quotes.

MYSQL='mysql AMORE -u username -ppassword -h localhost -e'
QUERY="SELECT "'*'" FROM amoreconfig" ;# <-- "double"'single'"double"
eval $MYSQL "'$QUERY'"

Bonus: It also reads nice: eval mysql query ;-)

Run a string as a command within a Bash script

You can use eval to execute a string:

eval $illcommando

Execute command as a string in Bash

I don't know what your final goal is, but you might instead consider using the following more robust way: using arrays in bash. (I'm not going to discuss the several syntax errors you have in your script.)

Don't put your commands and its argument in a string as you did and then eval the string (btw, in your case, the eval is useless). I understand your script as (this version will not give you the errors you mentioned, compare with your version, especially there are no dollar signs for variable assignments):

#!/bin/bash

echo "AVR-GCC"
elf="main.elf"
c="main.c"
gcc="avr-gcc -mmcu=atmega128 -Wall -Os -o $elf $c"
eval $gcc
echo "AVR-GCC done"

You'll very soon run into problems when, for example, you encounter files with spaces or funny symbols (think of a file named ; rm -rf *). Instead:

#!/bin/bash

echo "AVR-GCC"
elf="main.elf"
c="main.c"
gcc="avr-gcc"
options=( "-mmcu=atmega128" "-Wall" -"Os" )
command=( "$gcc" "${options[@]}" -o "$elf" "$c" )
# execute it:
"${command[@]}"

Try to understand what's going on here (I can clarify any specific points you'll ask me to), and realize how much safer it is than putting the command in a string.

Bash execute string as command without expanding escaped spaces

Us an array instead of a string:

#!/usr/bin/env bash

ARGSTR=('./executable' 'test file.txt' 'arg2=true')
exec "${ARGSTR[@]}"

See:

BashFAQ-50 - I'm trying to put a command in a variable, but the complex cases always fail.

https://stackoverflow.com/a/44055875/7939871

How do I execute a command string in BASH?

Did you try eval "$CMDEXEC" >> "$LOGFILE" ?

Bash: Executing a complex command in a string, capturing output and return code

As I was painstakingly going through typing up all this question, I finally thought of a working solution, which in hindsight is rather simple:

OUTPUT=$(eval "$CMD")
EXITCODE=$?

Since I've already typed all this out and was unable to google for this myself, I figured I'd just post this and let it be.

How can we execute a string command and then get the result of it to assign a variable in shell script bash

The solution is:

strCode=$(scontrol show jodid --dd $VALUE)
echo "${strCode}"

Execute command from string variable in unix shell script

It's better to store commands in functions rather than in variables. Functions are great at it. Variables, not at all.

string() {
    ps -e | less
}

string

You could use eval to execute a command that has redirections (>, <) and pipes (|), but I strongly discourage you from doing so.

eval "$string"    # please don't

Bash: execute a multi-command line string in a script

the point of your question is to execute command stored in string. there are thousands of ways to execute that indirectly. but eventually, bash has to involve.

so why not explicitly invoke bash to do the job?

bash -c "$commandLine"

from doc:

-c string

If the -c option is present, then commands are read from string. If there are arguments after the string, they are assigned to the positional parameters, starting with $0.

http://linux.die.net/man/1/bash

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