Intermediate Reading #man-pages #cli #git #curl

Reading Man Pages & CLI Help

5 exercises on decoding CLI synopses, flags, exit codes, and option descriptions from git --help, curl --help, and similar tools.

Key patterns for reading man pages and CLI help

[ ] = optional, <> = required placeholder, | = choose one
Exit code 0 = success; 128+n = killed by signal n (130 = Ctrl+C)
Short flags (-v) and long flags (--verbose) usually do the same thing
Check the description, not just the synopsis, for "Required" flags hidden in OPTIONS

0 / 5 completed

1 / 5

Read this excerpt from git --help:

usage: git [-v | --version] [-h | --help] [-C <path>] [-c <name>=<value>]
           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
           [-p | --paginate | -P | --no-pager] [--no-replace-objects]
           [--bare] [--git-dir=<path>] [--work-tree=<path>]
           [--namespace=<name>] [--super-prefix=<path>]
           [--config-env=<name>=<envvar>] <command> [<args>]

In this synopsis, what do the square brackets [ ] around options signify?

2 / 5

Read this curl --help excerpt:

 -H, --header <header/@file>
              (HTTP) Extra header to include in the request when sending
              HTTP to a server. You may specify any number of extra
              headers. Note that if you should add a custom header that
              has the same name as one of the internal ones curl would
              use, your externally set header will be used instead of
              the internal one.

              If you send the custom header with no-value then its
              header must be terminated with a semicolon, such as
              -H "X-Custom-Header;" to send "X-Custom-Header:".

 -i, --include
              Include the HTTP response headers in the output.

 -o, --output <file>
              Write output to <file> instead of stdout.

A developer runs: curl -H "Authorization: Bearer abc123" -i https://api.example.com/users

What will the output include?

3 / 5

Read this git log --help excerpt:

-n <number>, --max-count=<number>
    Limit the number of commits to output.

--since=<date>, --after=<date>
    Show commits more recent than a specific date.

--author=<pattern>
    Limit the commits output to ones with author header lines
    that match the specified pattern (regular expression).

--grep=<pattern>
    Limit the commits output to ones with log message that
    matches the specified pattern (regular expression).

--all-match
    Limit the commits output to ones that match all given
    --grep, rather than ones that match at least one.

A developer runs: git log --author="alice" --grep="bugfix" -n 10

Without --all-match, what commits are shown?

4 / 5

In a man page, you see this section header:

EXIT STATUS
       0      Successful termination.
       1      An error occurred.
       2      Misuse of shell built-ins (per Bash documentation).
      128+n   Fatal error signal "n". For example, exit code 130
              means the program was interrupted by SIGINT (Ctrl+C).

A shell script checks the exit code after running curl. The command returns exit code 130. What happened?

5 / 5

A CLI tool's help output shows:

deploy [OPTIONS] <environment>

OPTIONS:
  --dry-run          Simulate the deployment without making changes.
  --timeout <secs>  Abort if deployment exceeds this duration. [default: 300]
  --force            Skip confirmation prompts.
  --rollback         Roll back to the previous version on failure. [default: true]
  --tag <image-tag> Docker image tag to deploy. Required.

ARGUMENTS:
  <environment>     Target environment (staging | production).

Which of the following commands will fail validation based on the help output?