NEW YORK, FEB. 20 -- The New York Post, in a heart-stopping reprieve from its final deadline, escaped journalistic oblivion today as owner Rupert Murdoch reached agreement with nine unions on a $22 million package of concessions.

"WRITE ON!" the 187-year-old tabloid announced in today's edition, whose publication was uncertain as late as Friday afternoon.

The agreement, reached at 2 a.m. today, 12 hours after Murdoch had threatened to close the paper, enables him to sell the Post to Manhattan real estate developer Peter S. Kalikow, who never surfaced publicly during the tense negotiations. Union officials remained skeptical toward Kalikow and his commitment to the paper he is buying for $37.6 million.

"We would like to believe that Mr. Kalikow is in the New York Post to stay, but it's hard to believe in someone you haven't seen," said Jerry Cronin, head of the drivers' union.

Murdoch, who was forced by a congressional amendment to sell the Post so he could retain WNYW-TV, his New York television station, praised Kalikow, who is believed to share his conservative outlook. "He's a very ambitious man as well as a determined one," Murdoch said. He said Kalikow is "getting a newspaper with a fine staff {and} wonderful executives."

Kalikow has already had designers draw up a more subdued version of the racy tabloid, reducing the size and volume of its screaming headlines. He has designated Peter O. Price, owner of glitzy Avenue magazine, as his publisher in an effort to attract a more upscale audience.

But newspaper analysts question whether the Post, which lost $17 million last year, can ever turn a profit in its tabloid war with the New York Daily News and Newsday. And some employees question whether Kalikow is more interested in keeping the presses rolling or in obtaining the Post's valuable waterfront property between the Brooklyn and Manhattan bridges, worth about $30 million.

For the Post's 1,200 employees, the last-minute reprieve was a final twist on a daylong emotional roller coaster that hit bottom at 2 p.m. Friday, when they expected to leave the South Street building for the last time. Murdoch, a tenacious negotiator, had threatened to close the paper at 2 p.m. if the unions failed to come up with $24 million in savings over three years, and was reported to be making last-minute demands as the deadline neared.

But Murdoch, who had vowed not to stop the negotiating clock, appeared at the talks at the Grand Hyatt Hotel a few minutes before the deadline with a final proposal. He stopped the clock for a "final" 15 minutes, but when union leaders rejected the offer, Murdoch agreed to continue negotiations and did not set another deadline.

In the Post newsroom, where reporters and editors had been saying their farewells and drinking a final toast to the paper founded by Alexander Hamilton in 1801, there was a collective sigh of relief and a growing feeling that perhaps the Post would live to publish another day.

New York Gov. Mario M. Cuomo (D) played a backstage role in the negotiations, telephoning Kalikow and other participants in an effort to avert an impasse.

In the end, Murdoch settled for $2 million less than he said he would. Murdoch originally asked for the elimination of 79 jobs, wage cuts of 12 percent and a three-year salary freeze.

In the agreement announced today, 130 jobs will be cut, and the unions accepted a salary cut that was unspecified by management but that labor lawyer Theodore Kheel, representing the Post's unions, said would be $2.5 million per year for three years, bringing the total savings to $30 million. The pot will be sweetened by a $3 million bonus to employees to be paid by Murdoch in the first two years and a $2 million bonus from Kalikow in the third year.

Kalikow takes over the paper March 7, one day after the scheduled expiration of Murdoch's waiver from the Federal Communications Commission, which has allowed him to hold the Post and WNYW-TV. The FCC was barred from giving Murdoch an extension under an amendment that Sen. Edward M. Kennedy (D-Mass.) quietly attached to a stopgap funding bill late last year.

Kennedy has said that he believes that in fairness Murdoch should comply with federal cross-ownership prohibitions. Under the same amendment, Murdoch has said he plans to sell his Boston television station, WFXT-TV, to retain the Boston Herald, which has been sharply critical of Kennedy.

Many union employees said they felt betrayed by Murdoch because his ultimatum came after they had supported his bid to obtain a waiver of the FCC "cross-ownership" rules. Union leaders also questioned why Murdoch dealt only with Kalikow and refused to negotiate with bidders such as Leonard Stern, owner of the Village Voice, and Wilbert Tatum, owner of the Amsterdam News.

Murdoch, who bought the Post from Dorothy Schiff for $30 million in 1976, gave it a conservative tilt and a sensational approach that relied heavily on crime, sex and gossip. It relentlessly attacked liberal targets such as Kennedy while boosting favored politicians such as Mayor Edward I. Koch (D), whom the Post virtually drafted for an unsuccessful run for governor in 1982.

But the Post was never able to capture more than 10 percent of the newspaper advertising market in New York, and with a recent cutback in the number of editions, its circulation has dropped to 500,000 from a high of nearly 1 million.

Against this backdrop, Kalikow "felt the paper was bleeding to death" and was unwilling to complete the purchase without the union concessions, said Howard Rubenstein, a spokesman for both Murdoch and Kalikow.