linux Commands

    alias - create names or abbreviations for commands
    apropos - search the manual page names and descriptions
    at [man page] - queue, examine or delete jobs for later execution

    bc [man page] - An arbitrary precision calculator language

    cal - displays a calendar
    cat [man page] - concatenate files and print on the standard output
    cd - change directory
    chgrp [man page] - change group ownership
    chmod [man page] - change file access permissions
    cksum [man page] - checksum and count the bytes in a file
    cp [man page] - copy files and directories
    csplit [man page] - split a file into sections determined by context lines

    date [man page] - print or set the system date and time
    dd [man page] - convert and copy a file
    du [man page] - estimate file space usage

    egrep [man page] - print lines matching a pattern
    export - set an environment variable

    fgrep [man page] - print lines matching a pattern
    find [man page] - search for files in a directory hierarchy
    fold [man page] - wrap each input line to fit in specified width

    grep [man page] - print lines matching a pattern
  
    head [man page] - output the first part of files

    join [man page] - join lines of two files on a common field

    logrotate [man page] - rotates, compresses, and mails system logs
    ls [man page] - list directory contents

    mkdir [man page] - make directories
    mv [man page] - move (rename) files
    mount [man page] - mount a file system

    nl [man page] - number lines of files

    od [man page] - dump files in octal and other formats

    pwd [man page] - print name of current/working directory

    rgrep [man page] - print lines matching a pattern
    rm [man page] - remove files or directories

    scp - secure copy (remote file copy program)
    ssh - OpenSSH SSH client (remote login program)

    tail [man page] - output the last part of files
    tar [man page] - The GNU version of the tar archiving utility
    tee [man page] - read from standard input and write to standard output and files
    time [man page] - run programs and summarize system resource usage
    touch [man page] - change file timestamps

    vim - Vi IMproved, a programmers text editor
  
    watch [man page] - execute a program periodically, showing output fullscreen
    wc [man page] - print newline, word, and byte counts for each file
    whoami [man page] - print effective userid

yes [man page] - output a string repeatedly until killed