Results for “command substitution”
Small, practical examples. Search by task or narrow things down below.
Observe command substitution’s trailing-newline removal
Bash Scripts: Command substitution removes trailing newlines while preserving embedded ones.
Bash Scripts✓ Tested
Return text from a shell function
Capture a function’s output with command substitution.
function✓ Tested
Capture output while handling a failed command
Bash Scripts: An assignment inherits the status of its command substitution, allowing both output and status to be handled.
Bash Scripts✓ Tested
Compare two generated sorted streams
Bash Scripts: Process substitution lets a command consume another command’s output as a file-like input.
Bash Scripts✓ Tested
Return a value through a named output variable
Bash Scripts: A Bash nameref can update a caller-supplied variable without command substitution.
Bash Scripts✓ Tested
Bound a command execution time
Linux Commands: Use timeout and handle status 124 as an expected time limit.
Linux Commands✓ Tested
Branch on a command’s exit status
Linux Commands: Branch on a command’s exit status using GNU/Linux commands in an empty practice directory.
Linux Commands✓ Tested
Build an image with a default command
Docker / Compose: Build an image with a default command with a complete introductory Dockerfile.
Docker / Compose✓ Tested
Capture a command’s output
Bash Scripts: Capture a command’s output with a small standalone Bash program.
Bash Scripts✓ Tested
Capture a command’s success-stream output
PowerShell: Assignment collects output values without requiring text redirection to a file.
PowerShell✓ Tested
Check for an installed command
Bash Scripts: command -v checks command resolution without assuming a specific installation path.
Bash Scripts✓ Tested
Check whether a command can be resolved
PowerShell: Get-Command with a local error override supports an expected missing-command lookup.
PowerShell✓ Tested