Skip If File Exists

skip-if-file-exists

Tiny POSIX shell filter from EDirect. It reads file paths from stdin one line at a time and echoes only those paths for which test -f is false.

Quick Start

• Command: ... | skip-if-file-exists
• Local executable: /home/vimalinx/miniforge3/envs/bio/bin/skip-if-file-exists
• Input contract: newline-delimited file paths on stdin

When To Use This Tool

• Skipping already materialized output files in shell pipelines
• Filtering a list of target paths before download, fetch, or conversion steps
• Building idempotent “only process missing outputs” loops around EDirect-style file lists
• Removing existing files from a queue without writing a custom while read shell block

Common Patterns

# Keep only missing paths
printf '/tmp/a\n/etc/hosts\n/tmp/b\n' | skip-if-file-exists

# Generate only missing downloads
printf '%s\n' *.xml | skip-if-file-exists | xargs -r -n 1 download-step

# Use inside a while-read workflow
some_path_generator | skip-if-file-exists | while read -r path; do
  touch "$path"
done

Recommended Workflow

1. Generate a newline-delimited stream of candidate file paths.
2. Pipe that stream through skip-if-file-exists.
3. Feed the surviving missing paths into xargs, while read, or another downstream executor.
4. Re-run the same pipeline safely; once files exist, they will be filtered out automatically.

Guardrails

• This tool does not execute commands. It is only a stdin-to-stdout path filter.
• It has no real -h, --help, or --version interface; invoking it with flags and no stdin simply produces no output.
• The implementation uses [ ! -f "$fl" ], so directories and other non-regular paths are treated as “missing” and will pass through.
• In local testing, /etc/hosts was correctly suppressed while nonexistent temp paths were echoed unchanged.