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In a given shell, normally I'd set a variable or variables and then run a command. Recently I learned about the concept of prepending a variable definition to a command:
FOO=bar somecommand someargs This works... kind of. It doesn't work when you're changing a LC_* variable (which seems to affect the command, but not its arguments, for example, '[a-z]' char ranges) or when piping output to another command thusly:
FOO=bar somecommand someargs | somecommand2 # somecommand2 is unaware of FOO I can prepend somecommand2 with "FOO=bar" as well, which works, but which adds unwanted duplication, and it doesn't help with arguments that are interpreted depending on the variable (for example, '[a-z]').
So, what's a good way to do this on a single line?
I'm thinking something on the order of:
FOO=bar (somecommand someargs | somecommand2) # Doesn't actually work I got lots of good answers! The goal is to keep this a one-liner, preferably without using "export". The method using a call to Bash was best overall, though the parenthetical version with "export" in it was a little more compact. The method of using redirection rather than a pipe is interesting as well.
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The easiest way to set environment variables in Bash is to use the “export” keyword followed by the variable name, an equal sign and the value to be assigned to the environment variable.
We can set variables for a single command using this syntax: VAR1=VALUE1 VAR2=VALUE2 ... Command ARG1 ARG2...
To set an environment variable, use the command " export varname=value ", which sets the variable and exports it to the global environment (available to other processes). Enclosed the value with double quotes if it contains spaces. To set a local variable, use the command " varname =value " (or " set varname =value ").
To create a variable, you just provide a name and value for it. Your variable names should be descriptive and remind you of the value they hold. A variable name cannot start with a number, nor can it contain spaces. It can, however, start with an underscore.
FOO=bar bash -c 'somecommand someargs | somecommand2' If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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