<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I just find <a href="http://www.shellcheck.net" class="">http://www.shellcheck.net</a> is an awesome website for learning shell.<div class="">But it recommend use double quote for most case when I use ‘$'</div><div class=""><br class=""></div><div class=""><span style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px; background-color: rgb(0, 0, 0);" class="">$ shellcheck myscript</span><br style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px;" class=""><span style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px; background-color: rgb(0, 0, 0);" class=""> </span><br style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px;" class=""><a class="linelink" style="text-decoration: underline; color: rgb(128, 128, 255); font-family: Consolas, 'Courier New', monospace; font-size: 13px;">Line 1:</a><br style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px;" class=""><span style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px; background-color: rgb(0, 0, 0);" class="">ssh $EC2_BACKUP_FLAGS_SSH -o StrictHostKeyChecking=no -v ubuntu@$EC2_HOST \</span><br style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px;" class=""><span class="info" style="color: rgb(32, 255, 32); font-family: Consolas, 'Courier New', monospace; font-size: 13px;"> ^-- <a href="https://github.com/koalaman/shellcheck/wiki/SC2086" target="_blank" class="wikilink" style="color: rgb(128, 128, 255);">SC2086</a>: Double quote to prevent globbing and word splitting.</span><br style="color: rgb(192, 192, 192); font-family: Consolas, 'Courier New', monospace; font-size: 13px;" class=""><span class="info" style="color: rgb(32, 255, 32); font-family: Consolas, 'Courier New', monospace; font-size: 13px;"> ^-- <a href="https://github.com/koalaman/shellcheck/wiki/SC2086" target="_blank" class="wikilink" style="color: rgb(128, 128, 255);">SC2086</a>: Double quote to prevent globbing and word splitting.</span></div><div class=""><span class="info" style="color: rgb(32, 255, 32); font-family: Consolas, 'Courier New', monospace; font-size: 13px;"><br class=""></span></div><div class=""><font face="Consolas, Courier New, monospace" size="2" class="">We really need use double quote in this case?</font></div></body></html>