---
layout: page
category-page: intermediate
category-title: Intermediate commands
tags: bash shell terminal
author: Marco Farace
title: bash
---

Bash is an sh-compatible command language interpreter that executes commands
read from the standard input or from a file. Bash also incorporates useful
features from the Korn and C shells (ksh and csh).<br>

<h3>Flags</h3>
<ul>
    <li>-c: If this option is present, then commands are read from
        string.  If there are arguments after the string, they are
        assigned to the positional parameters, starting with $0.
    </li>
    <li>-i: If this option is present, the shell is interactive.</li>
    <li>-l: Make bash act as if it had been invoked as a login shell.</li>
    <li>-r: If this option is present, the shell becomes restricted.</li>
    <li>-s: If this option is present, or if no arguments remain after
        option processing, then commands are read from  the  standard
        input.   This  option  allows the positional parameters to be
        set when invoking an interactive shell.
    </li>
    <li>-s: List only the name, line and time fields.  This is the default.</li>
    <li>-T: Print a character after the user name indicating the state of the
        terminal line: `+' if the terminal is writable; `-' if it is not;
        and `?' if a bad line is encountered.
    </li>
    <li>-u: Print the idle time for each user, and the associated process ID.</li>
    <li>am I: Returns the invoker's real user name.</li>
    <li>file: By default, who gathers information from the file /var/run/utmpx.
        An alternative file may be specified.
    </li>
</ul>