this is also used for soft suggetsions to do something. タバコを消せばいい if you could put out your cigarette
ichidan (regular group 2) verbs replace -ru with -reba たべる (taberu) → 食べれば (tabereba). godan (regular group 1) verbs change last kana to -e column and add -ba. 行く (iku) → 行けば (ikeba)
The following is not good Japanese - えば can't be used in sentences of the form "If X then please do Y." (BAD) 彼がそちらに着けば、知らせてください。 If he arrives there, let him know. Instead -tara can be used. (GOOD) 彼がそちらに着いたら、知らせてください。 When he arrives there, let him know.
えば can be used if the following sentence is expressed as a likely outcome. (GOOD) 彼がそちらに着けば、知らせてくれるでしょう。 I guess you'll let me know if he turns up there.
what is the differences between tara and eba? wakarimasen
yep, check the bottom of this page: [Conditionals] different from my explanation tho.
simply, ~[tara] seems to have more of an impression of "when", not just if. eg: 東京に来たら、是非連絡してください。 when/if you come to tokyo, be sure to contact me. there is probably more on this in Tae Kim's pages.
Actually, the command form is okay as long as the えば is not a verb. (BAD) 田中さんが着ければ、教えてください。 (GOOD) よろしければ、食べてください。
I think that the English in ex #4977 is a little strange: 走れば、すぐに彼に追いつくだろう。 You will soon come up with him if you run. I think that either of the following better reflects the Japanese text. You will soon catch up to/with him if you run. You will soon overtake/pass him if your run. Also, in ex #4980, I think leave would be better than start. すぐに出発すれば電車に間に合うだろう。 You will be in time for the train if you leave at once. Depart could also be used in place of start (or leave), though it sounds a little misleading as there is a strong connection between trains and departing.
Maybe in ex #6441 ーたら form is more preferable? 「この薬を飲んだらよくなります。」 Some more examples: 秋が来れば雨が降る。(Expresses usual occasion. In this case 'と' may be used, but not 'ーたら') 誰か寄ってくれば赤ちゃんはたいてい泣き始める。(This one expresses usual occasion too. As in above example えば may be replaced with 'と', but not with ーたら) 新しくなければ買いません。 [If it is not new, I will not buy it.] (Expresses intention) 怖ければ後ろに隠れたほうがいい。[If it is scary, you'd better hide behind.] (This is not a command, but in this example なら would be better, I think).
Okay, let me see if I've got this straight... 「えば」 and 「たら」 are similar, but 「えば」 is used to express more of a cause-and-effect sort of relationship, and that's why it's used to express natural consequences. 「たら」 has less of a cause-and-effect tone, and it implies "when" or "after" more than 「えば」.
eba alaways indicate a positive effect which kara can be positive or negative for example kuruma ga areba iroirona basho ni ikemasu. if you have a car you can go to different places