mirror of
https://github.com/nix-community/impermanence
synced 2024-09-20 05:51:58 +00:00
43 lines
1.3 KiB
Bash
Executable file
43 lines
1.3 KiB
Bash
Executable file
#!/usr/bin/env bash
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set -o nounset # Fail on use of unset variable.
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set -o errexit # Exit on command failure.
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set -o pipefail # Exit on failure of any command in a pipeline.
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set -o errtrace # Trap errors in functions and subshells.
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shopt -s inherit_errexit # Inherit the errexit option status in subshells.
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# Print a useful trace when an error occurs
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trap 'echo Error when executing ${BASH_COMMAND} at line ${LINENO}! >&2' ERR
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# Get inputs from command line arguments
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if [[ "$#" != 3 ]]; then
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echo "Error: 'mount-file.bash' requires *three* args." >&2
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exit 1
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fi
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mountPoint="$1"
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targetFile="$2"
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debug="$3"
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trace() {
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if (( "$debug" )); then
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echo "$@"
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fi
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}
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if (( "$debug" )); then
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set -o xtrace
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fi
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if [[ -L "$mountPoint" && $(readlink -f "$mountPoint") == "$targetFile" ]]; then
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trace "$mountPoint already links to $targetFile, ignoring"
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elif mount | grep -F "$mountPoint"' ' >/dev/null && ! mount | grep -F "$mountPoint"/ >/dev/null; then
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trace "mount already exists at $mountPoint, ignoring"
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elif [[ -e "$mountPoint" ]]; then
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echo "A file already exists at $mountPoint!" >&2
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exit 1
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elif [[ -e "$targetFile" ]]; then
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touch "$mountPoint"
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mount -o bind "$targetFile" "$mountPoint"
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else
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ln -s "$targetFile" "$mountPoint"
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fi
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